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A ‘locking-bolt’ demountable shear connector (LBDSC) is proposed to facilitate the deconstruction and reuse of steel-concrete composite structures, in line with achieving a more sustainable construction design paradigm. The LBDSC is comprised of a grout-filled steel tube and a geometrically compatible partially threaded bolt. The latter has a geometry that ‘locks’ the bolt in compatible holes predrilled on the steel flange and eliminates initial slip and construction tolerance issues. The structural behaviour of the LBDSC is evaluated through nine pushout tests using a horizontal test setup. The effects of the tube thickness, strength of concrete slab, and strength of infilled grout on the shear resistance, initial stiffness, and ductility of the LBDSC are assessed. The experimental results show that the LBDSC can achieve higher shear resistance and similar initial stiffness as compared to traditional welded studs. In addition, all tested LBDSCs exhibited slip capacities ranging from 14 to 32 mm and can be classified as ductile shear connectors according to Eurocode 4. A detailed finite element model was also created and found to be reliable to reproduce the experimental behaviour. Parametric studies were subsequently conducted using the validated model to study further parameters and generalise the experimental results. Due to the specific test setup, non-negligible uplift forces were generated in the connector and the potential implications are discussed.

Civil infrastructures are vulnerable to catastrophic failures when exceeding the limit loading, requiring a reliable structural control mechanism, such as bracing systems, to enhance the integrity and stability of the structure. Bracing systems improve the performance of the structures by increasing the stiffness/strength of structures, the damping coefficient, and/or the energy absorption capacity. However, the functionality of these bracing systems is not controllable and may be altered after strong seismic events. Recently, the smart bracing systems based on multifunctional materials, particularly the shape memory alloy (SMA) and the magnetorheological fluid (MRF) have been developed. The superelasticity properties of SMA give the capability of recovering the original state after remarkable deformation. Furthermore, the SMA dissipates the energy of the applied load in the loading-unloading mechanism. The viscosity of MRF is variable and depends on the intensity of the applied magnetic fields. In the present study, a state-of-art hybrid SMA-MRF-based core bracing system is designed and in-house fabricated to enhance the structural behavior of the bracing system, including energy dissipation capacity and equivalent damping coefficient. Experimental tests have been conducted to illustrate the functionality of the system and the benefits of the SMA and the MRF systems. Finally, the seismic performance of the three-, six- and nine-story buildings equipped with the proposed SMA-MRF damping system is numerically assessed using nonlinear response history analyses. The results reveal that the proposed damping system significantly improves the seismic performance of the archetype buildings.

This study proposes an innovative carbon fibre reinforced polymer composite-geopolymer concrete (CFRP-GPC) system to improve the durability and structural performance of existing deteriorated reinforced concrete (RC) bridges. A rigorous experimental program is designed to investigate the transport mechanism of corrosive agents such as acids and chloride in the constituents via mechanical and microstructural analysis and to develop diffusion models for CFRP-GPC systems considering synergistic effects of temperature and pH fluctuations. Experimental results show that tensile strength of CFRP and epoxy resin reduces by up to 25% and the failure of composite mainly occurs at the fibre-epoxy interface after exposure to acid. The compressive strength of geopolymer concrete decreases by 66% and 61.3% while the mass loss reduces by 5.3% and 3.7% for samples after exposure to the 10% and 32% hydrochloric acid solution, respectively. The diffusion coefficients of the constituent materials vary from 10-8 to 10-6 mm2/s whilst the diffusion rate within the CFRP is the lowest due to the presence of carbon fibres. Furthermore, a computational model is established to evaluate the performance of the proposed hybrid system in improving long term durability performance of a roadway geopolymer concrete bridge in Australia. The numerical results indicate that the proposed CFRP-confined GPC can substantially impede the acid diffusion into the bridge column, and reduce the level of diffusion and thereby improve the service-life. Parametric study shows that the diffusion rate in CFRP-GPC columns increases up to 58% and 394% for epoxy and CFRP when temperature elevates from 23 °C to 80 °C. In addition, elevation in the exposure temperature from 23 °C to 80 °C increases the mass loss to 22% and 25% under pH = 1 and 7. The findings of this research provide a framework for durability design of hybrid CFRP-GPC systems.

This paper proposes a novel damage detection and localization method of civil structures using a windowed Long Short-Term Memory (LSTM) network. A sequence of windowed samples are extracted from acceleration responses in a novel data pre-processing pipeline, and an LSTM network is developed to classify the signals into multiple classes. Predicted classification of a signal by the LSTM network into one of the damage levels indicates the presence of damage. Furthermore, multiple structural responses obtained from the vibration sensors placed on a structure are provided as input to the LSTM model, and the resulting predicted class probabilities are used to identify the locations with a high probability of damage. The proposed method is validated on the experimental benchmark data of the Qatar University Grandstand Simulator (QUGS) for binary classification, as well as the Z24 bridge benchmark data for multiclass damage classification associated with different levels of pier settlement and the numbers of ruptured tendons. The results show that the proposed LSTM-based method performs on par with the one dimensional convolutional neural network (1D CNN) on the QUGS dataset and outperforms 1D CNN on the Z24 bridge dataset. The novelty of this paper lies in the use of recurrent neural network-based windowed LSTM for multiclass damage identification and localization using vibration response of the structure.

Failure of unreinforced masonry following the 2011 Christchurch earthquake demonstrated that many masonry strengthening solutions were inadequate for the peak ground accelerations that were experienced, and also that many of the failures were associated with underperformance of masonry anchors. Recent in-situ pull-out tests of anchors in vintage masonry structures has identified that in these tests, the failure is predominantly via splitting of the masonry units. This finding is in contrast to current design approaches that only consider failure via the formation of a cone or wedge, or masonry unit extraction. To further examine the potential for unit splitting prior to the failure modes identified in current design approaches, a laboratory campaign investigating masonry unit properties and anchor pull-out capacities, covering quasi-static, cyclic and impact loading of anchors and also incorporating the influence of quality of installation is reported here. The results of this campaign confirm that the unit splitting is an important failure mode, which may explain the observed anchorage underperformance. It is further observed that whilst cyclic and impact loading, as well as poor quality of installation have a detrimental effect on anchor performance, performance nonetheless exceeds published characteristic strengths. Additionally, as part of the laboratory campaign, a simple method for supporting masonry test units has been developed which has demonstrated good replication of the in-situ test results.

This study presents an analytical model for the load-moment (P-M) interaction diagrams of circular geopolymer concrete (GPC) columns reinforced with glass fiber-reinforced polymer (GFRP) bars and GFRP helices. The analytical P-M interaction diagrams of GPC columns were developed using the layer-by-layer numerical integration method. The analytical predictions of GFRP reinforced GPC columns were then validated against the experimental results on the behaviour of GFRP reinforced GPC columns under different loading conditions. It was found that the developed analytical model predicted the load and moment capacities of GFRP reinforced GPC columns with good accuracy. Further, a parametric study showed that the influence of increasing the compressive strength of GPC was more pronounced on P-M interaction diagrams of GPC columns under concentric and low levels of eccentric axial loadings. Also, the increase in longitudinal and transverse reinforcement ratios resulted in significant improvements in the load and moment capacities of GPC columns reinforced with GFRP bars and GFRP helices.

In this experimental study, Glass Fiber Reinforced Polymer (GFRP) plates were used to retrofit timber I-joists having a top flange-notch or a web-hole. Three types of GFRP reinforcing plates were used to retrofit and test 27 flange-notched and 27 web-holed I-joists for 3.65 m and 6.1 m span lengths. Another 200 I-joists were also tested to compare the performance improvement of the GFRP retrofitted I-joists. These I-joists had two different sizes of flange notch (100 mm × 100 mm and 100 mm × 150 mm) and two different diameters (150 mm and 200 mm) of web-hole located at different locations from the support. Although North American codes do not allow any form of a notch in the flange of I-joist, the current study shows that full capacity restoration can be achieved with proper retrofitting. From the four-point bending test of the I-joists, it is observed that GFRP plates can improve the structural capacity of retrofitted flange-notched or web-holed I-joists up to 605% and 106%, respectively, compared to the capacity of I-joists with a flange notch or a web hole, respectively. Two prediction models proposed here can predict the structural capacity of the retrofitted flange-notched and web-holed I-joists with different GFRP reinforcements with reasonable accuracy.

Seismic response of masonry towers has been widely studied, whereas research on their behavior under other dynamic forces is not common. The aim was to study the dynamic effects of bell swinging on a masonry tower, evaluating the response through different approaches. For this purpose, the south tower of the National Palace of Mafra was adopted due to its slenderness and its four swinging bells located at 49 m height. Dynamic identification tests allowed to determine the tower’s dynamic properties aimed at calibrating a numerical model. Frequency analyses assessed possible resonance effects by comparing the frequencies of the excitations with those of the tower. Nonlinear dynamic analyses evaluated the response in terms of displacements and cracking, while nonlinear static analyses determined damage patterns assuming different load combinations. Variations of structural stiffness and intensity of the forces were also studied. The results demonstrated that the tower, subjected to bells action, remains within the elastic range with a high safety level. Moreover, crack patterns correspond to local damage, which do not compromise the stability of the structure. Finally, parametric analysis allowed to obtain equivalent static load factors for bells of the Spanish system., This work was performed in the University of Minho with the funding from the ELARCH Program (Euro-Latin America partnership in natural Risk mitigation and protection of the Cultural Heritage), an Erasmus Mundus Action 2 Partnership (552129-EM-1-2014-1-IT-ERA MUNDUS-EMA21) by the European Commission and coordinated by the University of Basilicata, Italy.

This investigation evaluated the feasibility of combining lightweight concrete (LWC) and engineered cementitious composite (ECC) in specific configurations to develop a lightweight hybrid composite with improved impact resistance. In this study, three mixtures were investigated: one LWC mixture fully produced with lightweight fine and coarse expanded slate aggregates; one ECC mixture developed with polyvinyl alcohol fibers (ECCP); and one ECC mixture developed with steel fibers (ECCS). For testing, cylindrical specimens and small-scale beams were constructed in a two-layer composite system having different configurations (i.e., different arrangements and depths). Additional specimens fully cast with LWC, ECCP, and ECCS were tested for comparison. The interface bond strength between LWC and either ECCP or ECCS was also evaluated. The performance of the developed composites was assessed under static flexural loading and drop-weight impact. The results showed that both ECCP and ECCS could achieve a good bonding with LWC substrate, i.e., above 90% of that measured for the monolithic LWC specimens, even with no surface preparations (i.e., roughening or using shear keys). Combining LWC with either ECCP or ECCS generated novel lightweight hybrid composites that can offer superior performance for different structural lightweight members exposed to high impact loading. For given arrangement and depth, the LWC-ECCS composite exhibited higher mechanical and impact performance whereas the LWC-ECCP was distinguished by achieving an excellent impact resistance at a lighter self-weight.

Evolutionary node shifting is an effective approach to the shape optimization of spatial structures for excellent mechanical performance. In this paper, a novel shape optimization algorithm is proposed, which is applicable to complex gridshell structures of irregular geometries and non-uniform grids. With the objective of maximizing the structural stiffness, the nodal coordinates are iteratively updated according to the sensitivity information. The perturbation displacements referring to the inverse hanging method are applied to the initial flat model. By analysis, we found that the irregular grids give rise to non-smooth gradient fields, which results in jagged surfaces. To normalize the non-smooth gradient fields and to prevent the optimization process from falling into local optima, a double filter scheme is introduced in the process of optimization. A variety of examples are presented to demonstrate that the proposed algorithm can effectively solve shape optimization problems of general gridshell structures.

There is a global drive to promote and optimize the design of high performance buildings at low cost and minimum environmental impact. Although reinforced masonry construction is known for its better fire protection, structural durability, and construction cost reduction, its use is hindered by a lack of understanding of its resistance to earthquake loads. This research aims to quantify the effect of influential parameters on the seismic performance of Reinforced Masonry Shear Walls (RMSW) with masonry boundary elements (MBEs). A new system/configuration for RMSW with C-shaped masonry units has been proposed. A new experimental test setup was designed and built to capture the response of the lower panel of RMSW in a 12-storey building subjected to quasi-static loading protocol. Test results showed that the proposed system could provide the lateral strength and ductility required to resist earthquake events and that the average measured compressive strain was almost four times the limit specified in CSA S304-14. The results also showed that single out-of-plane support at the loading beam level was inadequate, leading to out-of-plane failure. When additional out-of-supports were provided, the failure mode changed to web crushing and buckling of vertical web reinforcement.

With the transition on planning and construction of offshore wind turbine (OWT) from North Europe to other regions like America and East Asia, challenges are proposed for the direct application of international OWT experience to these territories due to disparate natural condition like cyclones. This article is intended to evaluate the impact of cyclone on the long-term performance of an OWT to be installed in cyclone-prone regions. To have a comprehensive consideration on the aero-hydro-structural-soil interaction, an improved decoupled method is proposed and validated for an onshore wind turbine before its application to an OWT. Two cyclone models combined with two wave theories are considered in the fatigue evaluation of an OWT under different working status, and their implications on the final estimation of fatigue damage are compared and discussed. The results obtained from this study indicate that the fatigue life reduction which is caused by cyclone, for an OWT can be conspicuous for a reasonable cyclone strength and average recurrence interval. This implies that potential premature failure of an OWT tower and relevant economic losses can be encountered during its service life if the cyclone contribution to fatigue damage is ignored in the initial conceptual design.

Coastal bridges exposed to the marine environment always suffer from non-uniform corrosion along the pier height. As the non-uniform corrosion increase, the material properties of the pier in the splash and tidal zone deteriorates significantly, affecting the seismic performance of the pier. In this study, four scaled bridge pier specimens were designed and fabricated. These specimens were subjected to different level of electrical accelerated corrosion in the proposed splash and tidal zone. Then, the cyclic load tests were conducted on the four bridge pier specimens. The hysteretic behavior, loading capacity, ductility, energy dissipation capacity and mean curvature of each specimen were analyzed. It was found that with increasing corrosion level, the load capacity, ductility and cumulative energy consumption of the specimens decreased. When the corrosion was severe enough, the location of the plastic hinge will transfer from the pier bottom to the corroded zone.

In this work, the bending behavior of an advanced functionally graded ceramic–metal plate subjected to a hygro-thermo-mechanical load and resting on a viscoelastic foundation is studied using a simple higher-order integral shear deformation theory. The power-law function in terms of volume fraction is used to vary the elastic material constituents through the plate's thickness. The in-plane displacement field uses a sine shape function which changes linearly through the plate thickness to calculate the out-of-plane shear deformation. Both the linear and nonlinear influence of temperature and moisture concentration on the bending response are investigated. For the first time, a three-parameter viscous foundation model is used to study the bending response utilizing the damping coefficient in addition to Winkler’s and Pasternak’s parameters. The governing equations are derived using the principle of virtual displacement, and the analytical solution is obtained by the Navier method. Non-dimensional numerical results is validated by existing results in the literature. A parametric investigation is established to discuss the effects of the power-law gradient index, temperature rise and moisture concentration, elastic foundation coefficients, and the viscoelastic damping coefficient on the FGM plate's bending response.

Ever-increasing scarcity of land and demand for high-rise structures has significantly contributed to the use of combined piled raft foundations (CPRF) in soft ground. However, utility, design constraints and aesthetic considerations bring asymmetry to superstructures, making structures more vulnerable during seismic excitations. Traditional design practices involve designing superstructure elements and foundation considering fixity at the base of the superstructure and ignoring soil-structure interaction (SSI) which may result in under-estimation of forces and displacement in the system. Hence, the present study aims at developing new seismic design guideline pertaining to asymmetric single and multi-storied structure supported on CPRF embedded in soft clay. Some important parameters, such as torsional coupling mode of vibration and multi-storey idealisation involving the effect of higher modes are investigated incorporating seismic SSI effect. The study broadly reveals that the torsional to lateral period ratio considerably influence the seismic response of asymmetric structural system on the piled raft foundation due to the incorporation of SSI. Furthermore, multi-storey building idealisation gives a higher estimation of response compared to single storey idealization in superstructure and pile head which may be due to the effect of higher modes of vibration and SSI

This study assesses experimentally and numerically the cyclic loading response of reinforced concrete beams with web openings and shear-flexure strengthened carbon fiber reinforced polymer (CFRP) sheets using an external bonded technique. The influence of the beams on the reverse cyclic effect including the parameters of the hysteretic failure modes, stiffness degradation performance, energy dissipation, pinching width ratio, and ductility, are discussed. A numerical approach is employed to evaluate an innovative rectangular web opening and external bonding strengthening with an FRP sheet. A numerical model was used to validate the results of the tested specimens. Appropriate simulation techniques, which characterize the properties of constitutive materials, and a concrete damaged plasticity model were used for modeling development. Further, they are incorporated to apply models with new parameters. The results indicated that the use of CFRP as a strengthening system around the opening can significantly improve the overall stiffness capacity and beam behavior under cyclic loading. In particular, the increase in the load-carrying capacity over the control beam reached 63.43% for the beam with an opening in the shear zone and 73% for that with an opening in the flexural zone. The load–displacement hysteresis loops of the tested specimens were compared with those simulated by numerical models. Good convergence between the predicted and measured results was observed under all cyclic loading rates.

Fatigue damage assessment is critical for the structural design of the wind turbine nacelle chassis. However, existing fatigue damage indicators and assessment method cannot be both fast and accurate. In this paper, we propose a quantitative support vector regression-based fatigue damage assessment (SVR-FDA) method. First, the equivalent stress amplitude (ESA) is defined to simplify the fatigue damage indicator. Second, we establish the pre-calculated ESA database, including the ESAs of the wind turbine nacelle chassis under many varying wind flow conditions. Finally, based on the pre-calculated ESA database, we establish the SVR-FDA model, which can calculate the ESA of any given wind flow condition. A wind turbine nacelle chassis fatigue damage dataset, released by Goldwind, was applied to validate the proposed method. The results demonstrated that the SVR-FDA yielded the highest assessment accuracy for the lifetime ESA, as compared with four popular machine learning algorithms, including the least absolute shrinkage and selection operator, random forest, extreme gradient boosting, and deep neural network.

To overcome the concrete casting obstruction of the bottom slabs in prestressed concrete box-girders with corrugated steel webs (CSWs), transverse angle shear connectors were adopted in some cases. The overall behavior of such steel–concrete structures highly depended on the shear behavior of the connectors. Seven large-scale push-out specimens, with different height and spacing of shear connectors, were tested to examine the shear performance of transverse angle shear connectors. The failure modes, load-slip relationships, ultimate shear strengths, initial stiffness and ductility of specimens were explored. Based on the experimental results, this study suggests that both of the connector height and spacing impacted the shear strength of transverse angle connectors. The initial stiffness of specimens improved with the increasing of both connector height and number. The ductile characteristic can also be observed in the load-slip relationship. Compared with traditional longitudinal PBL shear connector, the transverse angle shear connectors also showed apparent strength enhancement and acceptable ductile characteristic. The equation for angle shear connectors suggested in Eurocode 4 can be used for predicting the shear strength of transverse angle shear connectors with spacing ranged from 350 mm to 450 mm.

Steel-concrete composite beams have been used in bridge construction for decades. Novel demountable bolted shear connectors, that allow bridge disassembly and offer high level of prefabrication, are proposed for the connection of the deck with the steel beams, as an alternative to the conventional headed studs. In terms of sustainability, bolted shear connectors facilitate the replacement of deteriorating bridge components and therefore extend the bridge design life. Despite their effectiveness, research on steel–concrete composite beams with bolted shear connectors is limited. In order to expand the available literature, this paper develops a three-dimensional finite element model to investigate the behaviour of a novel demountable shear connector for precast steel–concrete composite bridges. The connector uses high-strength steel bolts, which are fastened to the steel beam with the aid of a special locking nut configuration that prevents the slip of the bolts within their holes. The accuracy of the proposed FE model is validated by comparing its predictions with the experimental results available in the literature. Once validated, the FE model was then used to conduct a parametric study to evaluate the effect of bolt height, diameter and tensile strength, bolt pretension and the compressive strength of concrete on the load-slip behaviour, the shear resistance, the slip capacity and the stiffness of the shear connectors.

In this study, a deep learning-based axial capacity prediction for cold-formed steel channel sections is developed using Deep Belief Network (DBN). A total of 10,500 data points for training the DBN are generated from non-linear elasto plastic finite element analysis, which incorporated both initial imperfections, as recommended by the Australian/New Zealand Standard (AS/NZS 4600:2018) and residual stresses as recommended by Moen et al. A comparison against experimental results found in the literature was conducted. It was found that the DBN was conservative by 9%, 6% and 8% for stub columns, intermediate columns, and slender columns, respectively. When compared against a typical shallow artificial neural network (Backpropagation Neural Network) and a typical machine learning model (Linear regression model based on PaddlePaddle), it was shown that DBN performed around 2% better than both with the same training data. When the same comparison was made for both the Effective Width Method and the Direct Strength Method, it was found that they were conservative by 15%, 13%, and 15%, respectively. Based on the DBN output data, new and improved design equations for AS/NZS 4600:2018 were proposed.

This paper presents the application of a multi-target digital image correlation method (MT-DIC) to investigate the structural performance of structures with flat steel surfaces based on an experimental program. The displacement of a regular pattern of colored labels using the MT-DIC method and the obtained results are subsequently used to get deformations, strains, relative displacements, tension fields, and hysteresis curves of two steel plate shear walls models subjected to cyclic loading at different drifts ratios. MT-DIC operations are carried out based on a code written in the commercial software MATLAB. Results showed that the MT-DIC method is capable of capturing the in-plane deformations of the steel plate shear walls with an accuracy of 0.2 mm. The relative displacement of colored labels is used to extract the strain contours on the steel surface. The results show that the presented method can be used to extract and study the tension field angle and pattern of the steel plate shear wall under lateral load. The direction of the main compression strains is also used to study the buckling waves and pattern. Hysteresis curves of tested specimens are also obtained using this approach and compared with experimental results, which show a good agreement.

This study investigated the capacity of finite element modelling (FEM) approaches to predict the experimentally obtained behaviour of concrete-filled spiral-welded stainless-steel tube (CF-SWSST) short and long columns. Using the ABAQUS software, FEM was carried out of 24 CF-SWSST column tests. Nominal outside diameter to thickness ratios, effective length to diameter ratios and load eccentricity to diameter ratios equal to 51–114.5, 4.5–12.0, and 0–0.4 had been considered for the tests that were modelled. The distinct spiral weld seam geometry of the SWSST was explicitly considered in the FEM. Widely reported and accepted FEM modelling approaches and material models were adopted for this work. The concrete damaged plasticity model was utilised for the concrete core, while the stress–strain behaviour of stainless-steel was modelled using a modified Ramberg-Osgood relationship. On average, the capacities predicted by the FEM for the CF-SWSST columns were found to be non-conservative. The non-conservativeness was higher for specimens under concentric axial loading and increased with column and section slenderness. The actual to predicted capacity ratios were much closer to 1.0 for eccentrically loaded CF-SWSST columns, with conservative capacities predicted for eccentrically loaded specimens with the smallest section slenderness. For load eccentricity to diameter ratios of 0.15 and 0.4, there was negligible difference in the prediction conservativeness. Compared to analogous concrete-filled spiral-welded mild-steel tube columns, the FEM predictions obtained for the CF-SWSST columns were notably less conservative. This suggested that separate material constitutive models may be warranted for the FEM of CF-SWSSTs compared to their mild-steel counterparts. For the modelled eccentrically loaded specimens, the FEM predicted globally flexurally deformed states which agreed with those obtained experimentally, though the local buckling patterns were not replicated. In addition, the FEM qualitatively captured the experimentally obtained bending stiffness and strain variations. A modelling sensitivity study found that the FEM results were effectively equivalent even when the SWSSTs were modelled as plain seamless tubes.

The mechanical behavior of rockfall impacts on shed slabs was studied in three aspects: the rockfall impact force, the inertia effect coefficient, and the structural damage evaluation. A test model composed of a concrete slab and a cushion layer was constructed. Nine batches of impact experiments with energies ranging from 50 to 250 kJ were conducted. The dynamic impact model was established using LS-DYNA to analyze the dynamic impact response characteristics and inertia effect based on the SPH–FEM coupled method. Moreover, random sample expansions were calculated, and methods for assessing the impact force and inertia effect coefficient were proposed. In addition, the applicability of the proposed equation was verified by comparing the calculated results with relevant published experimental data and the Japanese calculation method of impact force. Furthermore, the velocity and mass of the rockfall were selected as the main control variables for damage assessment. A damage assessment index based on punching bearing capacity was established, and the level of damage was classified. Additionally, the influence of the parameters of the concrete slab and cushion layer thickness on damage assessment was analyzed. The impact resistances of the Ultra-High Performance Concrete (UHPC) and normal concrete slab were compared. The results demonstrated that the effect of impact force and the concurrent impact-induced inertia effect should be considered in structural designs. The larger the mass rockfall, the greater the damage sustained by the slab under the same impact energy. The compressive strength of concrete and the yield strength of steel have the greatest and least influence on the damage degree, respectively. A 90 cm-thick sand cushion on a slab increases the impact resistance of the slab by 25%–30%, compared with a 60 cm-thick sand cushion layer. Moreover, it was found that the UHPC concrete slab has good impact resistance, which is approximately twice that of the C40 concrete slab. One of the highlights in this paper is that the SPH–FEM coupled method is proposed to reproduce the physical phenomenon of sand pit-forming. Compared with FEM, SPH–FEM generates a simulated value that is closer to the experimental value.

A novel energy dissipation system named multi-toggle brace damper (MTBD) system is proposed in this paper. A theoretical mechanism for analysing the magnification factor of the MTBD system is established. Based on the finite element models (FEMs) simulated by ABAQUS, several single-story two-dimensional frame models with fluid viscous damper are investigated and compared with the theoretical mechanism. The magnification factors of the MTBD systems are compared with those of the traditional toggle brace damper (TTBD) systems. In addition, the dynamic responses of several three story three-dimensional reinforced concrete frame structures with different brace damper systems under various earthquake excitation levels are considered and investigated. The results show that the theoretical mechanism of the MTBD system is almost identical with the FEMs. Compared with the concrete frame with the TTBD system, the MTBD system has a larger amplification factor, a fuller hysteresis loop and a more obvious energy dissipation effect. The roof maximum displacements of the concrete frame structures with MTBD system are reduced by 41.1% on average. The MTBD system can significantly enhance the vibration control effect and reduce the dynamic response of the superstructures.

In modular steel building (MSB), connection is a critical part in the structural behavior and ability of load transferring. Previous MSB joints mainly use inter-connection plate or plug-in device, which ignore practical difficulties to hoist and install the modular unit. Therefore, this paper proposed an innovative corner-fitting connection, which is fully prefabricated and liftable. The seismic performance of the novel connection was analyzed by using finite element (FE) software ABAQUS. Numerical study of the novel joint was based on Simplified FE model and Detailed FE model. The developed FE model was verified by comparing with the test results of innovative connections in the previous references. The Simplified model for the joint was developed by using springs to connect the components. Five quasi-static cyclic loading FE analysis were performed on the innovative MSB connection to explore its load transferring capacity and seismic behavior. Results showed that weakening at the beam end can transfer the plastic hinge to the weakened position with little effect on the overall strength. The developed Simplified model can accurately predict the load–displacement curve and Von-mises stress of the joint. With these results, the cyclic response can be incorporated into the Simplified global model by defining the stiffness and dashpot coefficient of the spring. This paper proposed an engineering practical joint and Simplified FE model for seismic analysis of MSB, which is useful for the rapid development of this promising construction method.

This study examines the suitability of artificial neural networks (ANNs) for refined load rating estimation and bridge management. Bridge management for girder bridges commonly relies on AASHTO line girder (1D) analyses. Less conservative, more rigorous methods are permitted by AASHTO, but provide uncertain return on investment. This study demonstrates that a small set of refined analyses, coupled with ANNs, can be used as a predictive tool to anticipate the likely outcome for similar methods and bridges in a population. Two ANN-based load-rating prediction models were considered: (1) single-best-network, and (2) committee networks (CN). Load rating prediction accuracy was examined on a hybrid subset, consisting of hypothetical and real bridges representative of a steel girder bridge inventory. ANN-based prediction models were trained to map governing inputs (structural and geometric bridge characteristics) to load ratings obtained from 3D FE analyses. Prediction accuracy for bridges outside the training subset demonstrated that refined load ratings can be reliably estimated (about 5% mean absolute error) using a properly trained network model with optimized model complexity. The CN model provided improved prediction accuracy with higher confidence levels than the single-best-network approach, and exhibits less sensitivity to population size as the training sample size was reduced.

ultruded GFRP perforated plates are widely used in composite bridge and truss. Stress concentration is an inevitable focus of the structural design and analysis. This paper investigated the stress concentration of pultruded perforated plate under both uniaxial and biaxial stress. The hole’s radius r, the width w, height h of plate and stack layer were involved. Biaxial stress parametric Finite Element (FE) model of GFRP perforated plates were created. In terms of notch stress in GFRP perforated plate, the stress concentration of 0 degreesply is significant under unidirectional tension. When height to radius ratio is greater than 0.15 (2r/h > 0.15), the stress concentration factor (SCF) is suggested to be modified based on Tan’s model. The biaxial status of tension–compression is the governing load combination of GFRP perforated plate. The analysis method of biaxial status has been proposed in the paper. By arranging the layer angle of the non-0° layer of the laminate, the relationship between SCF of perforated plate and the anisotropic factor was found.

Concrete bridge piers are vulnerable to strong ground motions because of inducing significant residual drifts, which reduce the seismic resilience of bridges. A broad range of mitigation techniques is presented in the literature to reduce the vulnerability of bridge piers located in high seismic zones. Hybrid reinforced concrete piers are the most popular techniques to improve the seismic resilience of highway bridges. In addition, posttensioned segmental bridge piers are proposed as an alternative to expedite the construction procedure and also meliorate the performance of bridges in terms of residual deformations. However, very limited studies investigated the seismic performance of a whole bridge, especially for the purpose of comparing seismic resilience of the bridge columns. In this paper, a comparative study is implemented to explore the seismic vulnerability of a bridge reinforced with a hybrid configuration (i.e. combination of shape memory alloys (SMA) and normal-strength bars, and combination of high-strength and normal-strength bars) as compared to a reference conventional pier, which fully reinforced by normal-strength rebars. Moreover, a posttensioned segmental pier is considered to evaluate the strength and self-centering ability of this pier as compared to the monolithic ones. To do so, a 2D bridge model is developed in OpenSees simulation platform. Fragility curves are developed to assess the seismic vulnerability of the bridge model constructed with different piers. In this regard, a suite of 20 near-fault earthquake motions are applied to the bridge through Incremental Dynamic Analysis (IDA). Each of these records is scaled to 15 Peak Ground Accelerations (PGAs) ranging from 0.1 g to 1.5 g . The fragility curves reveal the chance of failure for each bridge model and aid in determining the impact of each pier on the seismic vulnerability of the bridge.

This study evaluates the effects of infills on the seismic resilience of special steel moment resisting frames. For this purpose, three structures of 4, 8 and 12 story are selected and designed in three different modes namely without infills, with Infills and with infills having openings. Finite element models are developed in OpenSees software. Seismic capacity and demand of structures are calculated using incremental dynamic analysis (IDA). Then, using statistical methods and probabilistic functions based on inter story drifts of the structures, fragility curves are obtained according to the HAZUS instructions. Finally, by quantifying damages, changes in seismic resilience are assessed. This makes it possible to relate the probability functions, fragility and resilience curves in an integrated approach. The results of the analysis show that infills may significantly reduce structural damages and an increase its resilience at different risk levels. The role of infills in increasing the resilience index is highlighted by the increase in risk level. This increase has been far more significant in low rise frames. It is also observed that the decreasing effect of infill openings in resilience index of high-rise buildings is less than low-rise ones although insignificant in some cases which can be overlooked.

Gradual changes of weight and geometry of vehicles combined with traffic values sometimes leads to old existing bridges having to be strengthened and retrofitted. The optimal solution to follow is based on the resistance capacity reserves of each structure, on the existing traffic level at the moment of retrofitting works and on the estimated future traffic. Almost all existing road bridges in Romania were designed according to national provisions/standards. Starting with 2010, following the European Community’s decision, the projects should be designed according to the Eurocodes and the existing bridges, must also comply with the new European load models. The process of checking existing bridges for the action of load models described in Eurocodes is a complicated task. However, the process for the evaluation of the bearing capacity reserves can be significantly simplified using a probabilistic approach. The approach presented in this paper is based on the effects, in terms of bending moments and vertical displacements, produced by several types of vehicles on the bridge superstructure. For presenting the use of this proposed methodology, typical bridge superstructures with precast concrete girders of different lengths were analyzed. The proposed methodology allows to establish the “vulnerability” of existing bridges on live loads.

There is a limited design guidance for practitioners regarding the shear design equations of circular-concrete members with fiber reinforced polymer (FRP) reinforcements, especially the case of incorporating FRP bars and spirals. The objective of this study is to enhance the methods used for estimating the shear capacity of reinforced concrete (RC) beams with FRP bars and spirals. A database of 44 circular concrete beams reinforced with FRP bars tested under shear were compiled from different experimental studies. Two proposed models based on approaches developed for rectangular sections, to predict the shear capacity of beams without and with stirrups, were compared with the selected available shear design equations. The shear strength estimated using the proposed models are slightly more accurate. The comparison indicates that the shear capacity of FRP-reinforced concrete members with circular cross sections may be determined with the V cf and Vsf approaches developed for rectangular sections provided that certain modifications are made to take into account the effective shear depth, equivalent breadth, the mechanical properties and geometry of GFRP spirals.

This article presents a study to evaluate the structural response of a cable-stayed bridge under a novel system, partially earth-anchored system with crossing cables at the main span. Six side-to-main span ratios, ranging from 0.24 to 0.39 in increments of 0.03, are tested for different bridge response parameters for both the superstructure and substructure. The loads considered in the analysis are the dead load and traffic load. Three-dimensional finite element models of the bridge are developed using structural analysis software SAP2000 and are validated based on the data available in the literature. From this study, it is found that the side-to-main span ratios have a significant effect on girder axial force and anchorage forces while having a very minor effect on cable axial forces. The results also show that the ratio does not affect the bending moment of the main span, but that when a small ratio is considered particular attention needs to be paid to the pier farther from the pylon to avoid uplifting. Deck vibration and longitudinal movement, as well as pylon longitudinal displacement, are not to be an issue for this super-long bridge.

The tubular steel structure is one of the most commonly used structural forms exposed in corrosive environments and its structural reliability should be addressed accordingly. However, the materials properties of corroded steel tubes were implicitly represented by those of corroded steel plates in previous studies. Experimental data and reliability analysis regarding the properties of corroded steel tubes (rather than plates) are still inadequate for reliability study. In response to these issues, this study conducted 96 tensile tests with respect to the different degrees of corrosion in circular steel tubes. Results demonstrated that the fracture mode of the corroded steel coupons changed to brittle fracture, and the necking phenomenon in the failure area gradually disappeared. Ultimate strength, yield strength and corresponding strain were remarkably degraded, and the yield plateau shortened and even disappeared as the degree of corrosion increased. Moreover, normal distribution can represent the yield strength of corroded steel tubes, and this distribution was verified by five hypothesis tests in this study. The mean yield strength of corroded steel presented a quadratic declining tendency at increasing corrosion rates. The time-dependent reliability analysis of corroded steel tubes was conducted in two corrosion scenarios (i.e. atmospheric and marine environments) and six levels of applied loadings (reflecting different safety levels). Finally, a set of trial material safety factors for ensuring sufficient safety margin was assessed, which can provide a reference for related specifications of steel tube structures subjected to atmospheric corrosion and/or marine environments.

This paper presents a combination of corrugated and flat plates to construct a seismically efficient compound section for steel shear walls. To assess the efficiency of the proposed section, a numerical and parametrical study was conducted using Finite Element (FE) software ABAQUS. The parametrical study included 45 different FE models consisting of three section types, five different length-to height ratios, and three values of plate thickness. The pushover analysis was performed for all the models. Both geometric and material nonlinearity have been considered in the analyses. The available experimental data was used to validate the FE modeling. The results indicated that the proposed wall improves the seismic parameters of the conventional steel plate shear wall. Besides the improvement of elastic stiffness, ultimate strength, and energy absorption capability, the proposed wall also reduces stress in the main frame. By reducing the imposed stress in the main frame, the ductility demand is reduced. As a result, a more economical system is achieved. Moreover, the necessary equations were suggested to achieve the push-over curve without requiring FE modeling, representing proper accordance with the FE results.

Estimation of basic material properties of masonry and understanding its compressive behaviour is the initial crucial steps in analyzing the performance of masonry buildings. Masonry being a complex and inelastic material has a large variation in mechanical properties such as compressive strength and modulus of elasticity. The variation for Indian masonry is even higher, as most of the manufacturing and construction process is performed manually. Mechanical characterization of solid clay bricks, mortar cubes (1:4 cement-sand proportion) and masonry prisms are performed using laboratory tests to determine the compressive properties. The non-linear stress–strain behaviour of masonry and its constituents is also presented. Based on the results of the present study and past literature, variation in mechanical properties of Indian masonry & its constituents is studied based on two different mortar grades (1:4 and 1:6). It is observed that these properties have a large portion of aleatory variability, due to variations in constituent materials and workmanship. The relationship between the compressive strength and elastic modulus of brick, mortar and masonry is also presented. Further, the relative performance of different empirical models in predicting the properties of masonry is compared and their efficacy is examined using the statistical and error-assessment parameters. Results showed that the compressive strength of the Indian masonry can be determined using most of the empirical relations available worldwide, with reasonable accuracy; however, the elastic modulus of masonry cannot be estimated with the same level of confidence.

In this study, the aeroelastic active control of a suspension bridge was studied using both experimental and numerical methods. Two flat plates attached on either side of the suspension bridge were used as the control surfaces. With a suitable rotation of the control surfaces, the turbulent flow around the bridge was modified, thus addressing the problem of aeroelasticity. An appropriate feedback control law was determined using a two-dimensional numerical model. Next, a wind tunnel experiment was conducted to validate the numerical results. The numerical analysis was conducted for a suspension bridge with a span of 3000 m. The effectiveness of the control was considered based on the arrangement of the control wings along the span of the suspension bridge. The ratio between the total length of the control surfaces and the span length was investigated. The coupling of the modes of the suspension bridge also affected the control results. It was suggested that aerodynamic stability could be enhanced by using a partially installed control surface. Moreover, the buffeting responses of bending and torsion of the suspension bridge could be reduced.

A new multi-scale numerical method is proposed to simulate crack propagation in reinforced concrete structures. First of all, a three-phase composite material model is used to build the concrete structures at meso-level. And a modified Weibull distribution model is introduced to describe further the microscopic characteristics of concrete. Then different constitutive relations are adopted for components of concrete and reinforcing bars. Next, the numerical program written in ANSYS parametric design language and tool control language is executed to investigate the fracture behavior of reinforced concrete structures. The program, which can check the development of multiple cracks, is greatly improved by contrast with traditional methods. Finally, relevant experiments are conducted for comparing with the numerical results. The analysis results indicate that the program has strong robustness. Moreover, a good agreement is achieved between simulation results and experimental observation.

This study is motivated by the lack of a systematic way to reproduce vertical human walking loads with a damped bipedal inverted pendulum (DBIP). Measurements of vertical human walking loads for a sample of 16 Chinese test subjects were carried out with a non-commercial force plate on rigid surfaces, in which 2393 single-step forces were recorded and analyzed. The mean value of all the test subjects’ average step frequency of free walking is 1.73 Hz, which is lower than the reported data for other populations. Most test subjects are naturally slow walkers, whose first four harmonics dynamic load factors are found to be less than the well-reported data. Only the first harmonic dynamic load factor has a clear trend to increase with the step frequency. The best linear fitting curve is given in the form of y = a(x + b), in which a = 0.24 and b = −0.82. A previously developed DBIP, which can be described by four dimensionless parameters, i.e. the dimensionless energy input, leg stiffness, leg damping, and the attack angle, is then applied to reproduce these measured forces. The simulated force with a minimum root of the mean square error to the measured force is selected and calibrated to the required step frequency and amplitude, which usually has a smaller peak force compared with the measured data. The adopted model inputs are illustrated as functions of step frequencies. The DBIP is applicable for modelling part of the test subjects’ walking loads on rigid surfaces at different step frequencies.

The geometry and the orientation of stiffener portray a crucial act in the analyses of stiffened plates. The authors have recently studied the response of bare plates under bending and buckling using a new method [1] , [2] known as the NURBS-Augmented finite element method (NAFEM). In the present work, this NAFEM is extended for investigating the response of plates with stiffeners subjected to free vibration. In its formulation, the numerical model has been made such that the straight and curved stiffeners can be placed arbitrarily with any disposition and need not be in line with the mesh grids. The stiffener’s stiffness matrix is expressed in terms of plate stiffness matrix, thus eliminating the requirement to model the stiffener separately as a beam element.

The axial compressive behavior of laminated bamboo lumber (LBL) columns with a chamfered section was investigated using 15 specimens with lengths varying from 600 mm to 3000 mm; all considered samples had same square cross section of 100 mm × 100 mm with 10 mm chamfers at each corner. Axial compression tests were carried out to analyze the impact of slenderness ratios on failure modes, strain and ultimate bearing capacity of LBL columns. Two failure modes were observed i.e. compression failure and buckling failure. Obtained results on the ultimate vertical strain and ultimate load showed a downward trend with the increase in slenderness ratios; the correlation between the ultimate strain, ultimate load and the slenderness ratios were fitted. The approximate solution method was adopted to reveal the lateral deflections of buckling columns by a quartic functional model. Based on the ideal elastic–plastic constitutive model and Hill failure criterion, FEM was carried out to simulate the axial compression tests. The simulation results agreed well with both test and theoretical results, which verified the feasibility of proposed methods used under similar working conditions in this paper.

A full-scale 3D thermo-mechanical Finite Element (FE) model was conducted in this research to investigate the effect of open-field thermal loads on the structural response of box-girder bridges. A box-girder bridge with a span of 50 m was analyzed for temperature, radiation and displacement fields using COMSOL Multiphysics. To verify the FE model, a full-scale experimental box-girder segment was constructed and instrumented with temperature, radiation and other sensors. From the experimental records, three days with extreme temperature and radiation measurements were selected. The stresses and displacements are discussed at specific points along the 24 h of the selected days and at specific times along critical sections. The FE analysis showed that the vertical and lateral stress distributions exhibited approximately similar behaviors to their corresponding temperature distributions with minor differences but with reversed sign. The results also showed that the maximum stress was compressive, which was −3.35 MPa in summer −3.83 MPa in winter. On the other hand, the maximum vertical and lateral displacements were 12.5 and 1.2 mm, respectively in summer and 2.7 and 1.9 mm in winter.

Vibrating Particles System (VPS) is developed based on some principles of physics in which the free vibration of a system with single degree of freedom including viscous damping is concerned. In this algorithm, each possible solution or vibrating particle seeks its equilibrium position in the search space. Despite of a relatively good exploration ability of the VPS algorithm, it is poor at exploitation and the convergence speed of this algorithm is also an issue in some cases. In this paper, the VPS algorithm is hybridized with the Migration-Based Local Search (MBLS) mechanism of the Biogeography-Based Optimization (BBO) algorithm with the strong local search capability to concentrate the search process around promising vibrating particles and locate the optimum solution more precisely. Three hybrid algorithms are developed based on how to use the VPS and MBLS methods as parallel, series and mixed series–parallel schemes. In order to evaluate the capability of the proposed hybrid methods in dealing with difficult structural optimization problems, a 24-story benchmark frame problem, a 10-story steel structure with 1026 structural members alongside a 20-story steel structure with 3860 members are optimized using presented algorithms. The findings affirm the robustness and efficiency of the proposed hybrid methods over the standard existing relevant approaches for optimum design of steel building structures.

Honeycomb structures are extensively used in the different applications. These structures are mainly made of Aluminum and Nomex materials. Nowadays, additive manufacturing (AM) technology has created a revolution in the manufacturing of different structures. In this paper, the honeycomb structure was manufactured using a fused filament fabrication (FDM) 3D printer. The effect of different geometrical parameters on the flexural properties of the 3D-printed honeycomb structures and their sandwich panels with the face-sheets made of E-glass/epoxy laminates were investigated. Three cell wall thicknesses, i.e., 1, 1.5 and 2 mm, were considered for the honeycomb structures. Moreover, two arrangements, i.e., vertical and horizontal directions, were regarded for the honeycomb structures. One of the disadvantages of the vertical honeycomb core panels is the weak bond between the core and the skins. Hence, the effect of printed thin layers between the skins and the vertical honeycomb core on the flexural properties of panels was also evaluated. Besides, the stress analysis of the samples was performed by a finite element simulation. The results showed that the structure consisting of the horizontal honeycomb core with wall thickness of 1.5 mm has the maximum normalized energy absorption. Comparing the obtained results with the available data in the literature manifested that the flexural properties of the honeycomb core sandwich structures are significantly improved by changing its core system from the Nomex and Aluminum materials to the printed system.

SiC/SiC ceramic matrix composites (CMCs) exhibit significant randomness of damage processes under load. In this study, a simplified simulation method was established based on the macroscopic damage constitutive model, characteristics of fewer test samples, and complex data sources for determining the randomness of the material behavior. Moreover, the established model was verified by introducing an uncertainty parameter to the constitutive model. By considering a typical high-dimensional nonlinear function as a numerical example, the reliability and error of the characterization methods were compared with specimens and studied in terms of the extreme-value interval, tolerance interval, evidence theory, and fuzzy set method with the distribution characteristics of single and mixed parameters. In conjunction with the sensitivity analysis, the randomness of the mechanical behavior was more evident at the damage stage, and the uncertainty of material behavior relied on the loading state. In addition, the correction method of the constitutive parameters and formal errors of the model were established using the Bayesian theorem to acquire additional data. Thereafter, the proposed method was employed for quantifying the uncertainty in the strength of the CMC turbine rotor blade. The determinacy results revealed that the failure risk could be more effectively evaluated by the strength analysis considering the uncertainty of the model, thus providing guidance toward structural design improvement aligned with engineering practice.

Highly ductile fiber–reinforced concrete (HDC) is characterized by a tensile strain–hardening behavior and high compressive toughness, which is expected to alleviate the cracking and durability problems induced by the brittleness of high–strength concrete (HSC). In this study, HSC was substituted with HDC to construct columns. Six reinforced HDC (R/HDC) columns and two reinforced HSC (R/HSC) columns were constructed and tested under compressive loads with different eccentricities. The crack patterns, failure modes, lateral deflection curves, load–displacement curves, and strains of concrete and rebars were investigated. The test results revealed that the R/HDC column has a better failure mode and cracking pattern compared to the HSC column. A good synergy work performance between HDC and rebars significantly improved the utilization of the longitudinal rebars. A calculation method for the bearing capacity of the R/HDC column was proposed. The calculated results were in good agreement with the experimental results. The load–moment interaction curves (N–M curves) of the R/HDC column were calculated and plotted. Subsequently, the effects of HDC compressive strength, HDC tensile strength, the reinforcement strength, and longitudinal reinforcement ratio on the bearing capacity of the R/HDC column were studied using parametric analysis. The results indicate that a high tensile strain can guarantee the efficient utilization of the tensile strength of HDC.

Given the randomness of corrosion and the variability of the constitutive model under corrosion conditions, the high-strength steel wire is selected as the basic component, and the constitutive model of steel wire is obtained through the tensile test of high-strength steel wire under different corrosion degrees. The innovation of this paper is the generation of random corrosion pits in numerical simulations. The random corrosion model of steel wire is developed by python, and the constitutive model of steel wire under different corrosion degrees is developed by FORTRAN, which is embedded in ABAQUS. The failure modes of high-strength steel wire under different random corrosion were analyzed. The results show that corrosion has little effect on elastic modulus and yield strength of steel wire. The ultimate strength and fracture strain of steel wire are decreased due to corrosion. The steel wire becomes brittle, and the breaking force is greatly reduced.

The Linked Column Frame (LCF) structural system is comprised of moment-resisting frames as the primary gravity load-carrying system and a combination of closely-spaced dual columns interconnected with link beams acting together with the moment-resisting frames as the lateral load resisting system. In this system, the link beams are designed to provide ductility and deform plastically. As the damages are concentrated to the links thus, the LCF rapidly returns to occupancy design performance while retaining architectural privileges of the non-braced steel frames. In this study, 3, 6, and 9-story frames equipped with LCF and resting on soil type II and IV are subjected to seven near and far-field earthquake records. These structures are designed based on the plan of SAC buildings using SAP2000, and then, nonlinear time-history analyses were carried. The results indicate that maximum roof drift of the structures on stiff soil (type II) has been insignificantly affected under both near and far-field earthquakes. In soft soils (type IV), drifts values increase by 6.85%, subject to both far and near-field earthquakes. Moreover, in contrast to the stiff soil, roof acceleration has decreased more when the structure is on soft soil, nearly 6.12%. The result of maximum inter-story drift ratios of the structures founded on soil type II illustrates that under an average of near-field earthquakes, drift ratios of 3 and 6-story structures have increased by 3.2%. On the other hand, the 9-story structure has encountered a decrease of 5.17%. Under an average of near-field earthquakes in soil type IV, a drift ratio of 3 and 6 and 9-story structures has grown to 5.11 and 11.2%, respectively, compared to the fixed-base models. In far-field earthquakes, drift values of 3 and 6-story LCF were reduced by 6.2%, and the 9-story structure has experienced an increase of 8.79%.

In the extension project of the China National Academy of Painting, the radial spherical plain bearing (RSPB) is used in a structural joint with an inserted plate. This new structural RSPB joint has complicated mechanical behaviors and universal rotational performance. In this work, the simulation and experiment methods were used to investigate the RSPB joint mechanical properties (uniaxial ultimate bearing capacity, failure mode) and reliability. Furthermore, the out-of-plane rotational performance was studied with eight finite models for the application. According to FEA and test results, this new RSPB joint has functional mechanical properties. It is useful in steel truss structures and provides a possibility for engineers to design hinge joints in building structures.

Based on piezoelectric ceramics' piezoelectric effect, a new type of piezoelectric ceramic friction damper (PCFD) is designed and manufactured to provide a reliable energy dissipation device for structural response control. In the PCFD, high-strength bolts limit the deformation of piezoelectric ceramics under voltage, and the resulting reaction force changes the preload of high-strength bolts, thereby realizing real-time adjustment of friction by adjusting the positive pressure on the friction surface. The influence of friction plates with different materials on the hysteretic performance of friction damper under different tightening torque is investigated by cyclic loading test to determine the friction plate's selection in the PCFD. The hysteretic performance test is carried out to evaluate the energy dissipation capacity of PCFD with different voltages, and the experimental results are compared with the theoretical values. The finite element model of PCFD is established to analyze the stress distribution of each component of the PCFD under different voltages. Based on the semi-active control characteristics of PCFD, the Takagi-Sugeno fuzzy neural network semi-active control system for frame structure with PCFD is designed. The adaptive learning function of the adaptive network-based fuzzy inference system (ANFIS) is used to generate fuzzy rules and fuzzy neural network controller (FNNC). Finally, the semi-active control simulation of three-storey frame structure model under seismic excitation is carried out by Simulink. The experimental and numerical results show that the PCFD designed in this paper has good energy dissipation capacity, and the maximum control force increases linearly with the increase of voltage. The combination of FNNC, which is established by ANFIS, and PCFD can effectively reduce the structure response.