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On-site observations show that several damages have occurred in CRTS II slab-type ballastless track system, such as crack and interface debonding between different structural layers, which will trigger the occurrence of some failure modes of CRTS II track slab. As the damages are the prior for specific failure modes, time-dependent reliability of CRTS II track slab should be conducted considering the uncertainties associated with both the failure mode and the damage, which is defined as the conditional time-dependent reliability in this study. To appropriately express the causal relationship among the failure modes and prior damages, a conditional limit state function (LSF) model is proposed with explicit expressions provided. With the aid of the proposed model, conditional time-dependent reliability of CRTS II track slab for two individual failure modes are investigated, which are the steel yielding failure mode under longitudinal cracking, and the vertical instability failure mode under interface debonding. Furthermore, conditional time-dependent system reliability of the track slab has also been analyzed considering four safety failure modes. The advantage of the proposed method is that prior damages have been accounted in establishing the failure criteria and incorporated in the formulation of time-dependent reliability, which provides a general formwork for structural reliability involving the causal relationship among the failure modes and damages.

Steel scaffolding is a very important component in formwork work to support further work. The purpose of this analysis is to review the maximum compressive strength that occurs in 3-story scaffolding before buckling occurs using the direct analysis method (DAM). The design of steel structures, which are generally slender, requires stability analysis. The result is influenced by imperfections (non-linear geometry) and inelastic conditions (non-linear material). In this final project, we use second-order inelastic analysis based on direct analysis method. The 3-level scaffolding model was analyzed using beam elements in the SAP2000 program with 6 variations of notional loads applied to the weak axis direction of the scaffolding pipe.The lowest compressive strength on 3-story scaffolding before buckling occurs is 18.24 kN with horizontal notional loads to the right on the first level scaffolding, left on the second level scaffolding and to the right on the 3rd level scaffolding. The results of the analysis show that the maximum compressive strength obtained results in a large displacement drastically in the iteration step. By using the analysis on the DAM method, the results obtained are more effective.

Jointed, prestressed columns have been shown to enable accelerated construction and to offer superior seismic performance, as compared with cast-in-place columns without prestressing. During an earthquake, such columns deform primarily through concentrated rotations at the joints, and special detailing at the ends of the columns prevents crushing and spalling. Unbonded prestressing steel, running vertically through the columns, provides a restoring moment that returns the columns to plumb after the ground motion stops. The use of prefabricated substructure elements speeds up the bridge assembly by eliminating building formwork, fixing steel, casting and curing concrete on-site. A variety of detailing strategies have been developed for jointed, prestressed columns, but their fundamental behavior is similar. More importantly, this behavior differs from that of conventional reinforced concrete columns for which current seismic code provisions were developed. This paper develops a displacement-based procedure for designing jointed, prestressed columns that is based on the framework provided by the AASHTO Guide Specifications for LRFD Seismic Bridge Design. To account for the unique characteristics of these systems, the design procedure introduces new performance criteria; it also provides recommendations for proportioning the prestressed and non-prestressed steel, calculating the effective column stiffness, and estimating the column displacement capacity. The focus of the paper is on columns with pretensioned strands and internal energy dissipaters, although the procedure would work for post-tensioned systems and those with external dissipaters as well. This design approach is critically evaluated through comparison to the results of both cyclic tests of cantilever columns and shaking table tests of a two-span bridge system.

Due to the fact that hollow-core slabs without formwork are produced without slinging loops (features of manufacturing technology), the issue of installation and transportation of these slabs has been solved. A constructive and technological solution is proposed for a slinging unit, arranged in the body of the slab, without the use of a slinging loop, and having only an anchor rod-dowel through which it is possible to directly sling the slab without using traditional slinging loops. The unit is designed with a reduced metal consumption and does not change the technology for manufacturing hollow-core slabs without formwork. Found and summed up a theoretical basis for calculating the bearing capacity of the proposed slinging unit, arranged in a hollow-core slab without formwork. It was revealed that the bearing capacity of the proposed slinging assembly, arranged in the body of a hollow-core slab, under the action of assembly loads, depends on the force of splitting the concrete of the protective layer located above the anchor rod-dowel of this assembly (all other things being equal). The theoretical data of the study were verified by full-scale tests of plates with slinging units arranged in their body, carried out in accordance with the proposed constructive and technological development. A utility model patent was obtained for the development of a loopless slinging unit for a hollow-core slab without formwork.

Thin-walled steel decks have been generally treated as permanent formwork in the routine design of steel-bars truss slabs, and their effects on the time-dependent behaviour of steel-bars truss slabs have not been quantified. The objective of this study was to propose design procedures for the time-dependent behaviour of steel-bars truss slabs accounting for the effects of soffit steel decks. For this purpose, two full-scale slab samples were tested for 9 months, with one slab subjected to non-uniform shrinkage and sustained loading and the other slab subjected to only non-uniform shrinkage. Typical design equations for reinforced concrete slabs and composite steel–concrete slabs were benchmarked against available test results to verify their applicability. Non-linear finite-element models were established to describe the time-dependent behaviour of steel-bars truss slabs, and simplified design procedures were proposed. It was found that the steel-bars truss sample subjected to non-uniform shrinkage had a mid-span deflection accounting for 52·4% of the total deflection; that the design methods in available composite structure standards significantly underestimated the long-term deflections; and that the proposed design procedures well predicted the time-dependent deflections of steel-bars truss slabs by considering the influence of the shrinkage gradient.

Determining the compressive strength of concrete in the early stages of ageing has been an increasingly relevant topic in recent years, particularly with regard to the safe removal of formwork from a structure or its part. The compressive strength of concrete which designates safe removal of formwork without damaging the structure can be referred to as "stripping strength". It is undoubtedly beneficial to be able to determine the moment of safe formwork removal in a non-destructive manner, i.e. without compromising the structure. Modern rebound hammer test methods seem to be a suitable instrument with which it is possible to reduce the length of technological breaks associated with concrete ageing to a minimum, and consequently, reduce the total cost of the construction. However, the use of these methods presents a number of challenges. As many conducted experiments have shown, there is no single conversion relationship (regression model) between non-destructive rebound hammer test methods and compressive strength. It is therefore advisable to always create a unique conversion relationship for each individual concrete. In addition, it must be noted that conventional regression analysis methods operate with 50% reliability. In construction testing, however, the most common is the so-called characteristic value, which is defined as a 5% quantile. This value is therefore determined with 95% reliability. This paper describes the construction of a so-called "characteristic curve", which can be used to estimate the compressive strength of concrete in a structure using rebound hammer test methods with 95% reliability. Consequently, the values obtained from the characteristic curve can be easily used for practical applications.

High-performance materials are increasingly being used in precast connections to improve their mechanical performance and simplify the construction process. In this study, a novel precast beam-column connection with an ultrahigh-performance concrete (UHPC) core shell is proposed, which works as the permanent joint formwork in the precast stage and the strengthening overlay during normal service. To investigate the seismic performance of the proposed connection, a total of three precast specimens and one reference monolithic specimen were tested through the quasi-static method. The main variables in this study were the thickness of the UHPC shell and the layout and ratio of stirrups in the joint zone. The test results indicated that the UHPC core shells effectively limited the shear behavior, delayed cracking in the joint zone, and provided plump hysteretic performance. With the assembly configuration, the proposed connection had good ductility and an efficient energy dissipation capacity. The UHPC shell configurations with variable stirrup layouts and ratios led to different crack patterns in the joint core zone. In addition, strengthened by the UHPC shells, the joint cores could be reinforced with fewer stirrups than demanded by code.

In this study, 3D finite element analyses are conducted to quantify the mechanical behavior of the post-tensioned concrete deck and improve its efficiency as well as structural performance. The detailed finite element (FE) models consisting of interactions between the constituents based on experimental results are presented and validated with three experimental specimens tested under one-point loading. The FE models are dedicated to improve the structural behavior of the deck by reducing inefficient concrete in the tensile zone with three different strategies. First, the hybrid concrete design with different composition is proposed using the lightweight concrete presented in current research. Also, glass fiber-reinforced polymer (GFRP) is employed to enhance the strength of proposed hybrid decks. Second, the polyurethane (PU) foams with different properties are placed in the tensile part of deck without any changes in the total depth of control FE model and then the strength of PU decks is enhanced by estimating the minimum required thickness of GFRP layer. Besides, the PU foam decks with the same volume of concrete as control FE model are simulated. Finally, a design with polyvinyl chloride permanent formwork is numerically evaluated and studied in details. Regarding the FE analysis results, the efficiency of proposed decks is confirmed in comparison with control specimens. Decreasing the weight of deck as proposed in this research leads to decrease in dead and earthquake load and consequently in size and cost of designing the different parts of structures.

In selecting the formwork work method, the things that need to be considered include cost, quality, and time. Comparison of several methods of formwork work is carried out to obtain the correct method. Comparisons were made to the Semi System formwork method and the Aluminum formwork method. To compare the two methods requires volume calculation, the multiplier coefficient referred to by the PUPR Regulation No. 28 / PRT / M / 2016, non-conformence data, and work duration. This data is processed into the need for the cost of formwork for the two methods based on the PUPR Ministerial Regulation Number 28 / PRT / 2016, the percentage of concrete defects due to formwork, and the scheduling duration presented in the bar chart. The two methods are compared based on the need for the cost of the work, the number of percent of quality, and the work duration. The comparison shows that the aluminum formwork method is superior in terms of cost (RAB). It is produced more efficiently by 3.4%. In terms of quality, this method results in less damage (concrete defects) to minimize repair costs later, and when the work reaches 43% more effective.

In recent years, the deterioration of harbor structures has become a matter for concern, and the establishment of effective repair methods has become urgent. In this study, a repair method for installing permanent formwork panels and filling them with underwater inseparable mortar is proposed as an effective section-restoring method for deteriorated concrete caisson sidewalls. To investigate the integrity between existing concrete and repaired parts as well as the effect of thickness increase due to panel installation, static bending tests of a flat-reinforced concrete (RC)-beam-modeled side wall used in caisson structures are conducted. The results obtained from this study are as follows: (1) by attaching the permanent formwork panels to the flat RC beam, the bending crack occurring load was improved by a factor of three, and the rebar yielding load and maximum load were doubled. This tendency was the same even when the RC beam had a cross-sectional defect. (2) The RC beam with the permanent formwork panels finally failed with diagonal cracks opening after the maximum load was reached. The ductility ratio at this time was approximately 6. To improve the deformation performance, it is necessary to apply shear reinforcement. (3) The analysis results by the fiber model assuming the complete adhesion of the permanent formwork panels, underwater inseparable mortar, and RC beam were performed, and the results were compared with the experimental results. As a result, it was clarified that the adhesion of each constituent material was retained until the yield of the main reinforcing bar. After that, pulling out of the main reinforcing bar from the concrete and damage to the permanent formwork panel became apparent. (4) The curvature of the cross-section at the yield of the main reinforcing bar was φyc = 0.007 m−1, and it was confirmed that the assumption of plane conservation was valid in the cross-section with a curvature less than that. This research is expected to promote the efficient maintenance of existing concrete caisson structures. As the amount of cement used and the construction period can be reduced, it is assumed that the environmental load can be reduced as well.

The problem of determining the moment of formation of normal cracks in bending reinforced concrete elements with a complex cross-sectional shape, clamped at one end in brickwork and operating under the action of a negative bending moment is considered. A technique for testing prototypes of hollow-core slabs without formwork is presented. The purpose of the experiment is to determine the angles of rotation of the support nodes of hollow-core slabs without formwork, embedded in brickwork. The design of an installation for testing experimental specimens until the moment of cracking is presented. A diagram of the arrangement of measuring instruments is given to determine the deformation of the support unit at the place where the slab is embedded in the masonry, the defl ection of the prototype at the place of load application, the deformation of the brickwork simulating the wall of a multi-storey building.

With the development of China's construction field, prefabricated building structure has gradually become a very common building structure in the current construction engineering by virtue of its many advantages in the actual construction field. Combined with the engineering practice, this paper summarizes the hoisting technology of precast composite slab and precast staircase in prefabricated building structure. This paper focuses on the optimization design of laminated plate support under the conditions of wood formwork and aluminum formwork system and the key and difficult points in the construction process, and puts forward a set of practical and feasible construction methods for prefabricated components. This paper focuses on the analysis of the design concept, materials, structural form, manufacturing technology, hoisting and installation, and construction technology of M-type light steel concrete composite slab. This paper discusses and summarizes the advantages and disadvantages of M-type light steel reinforced concrete composite slab at present, and analyzes its development and application prospects. At the same time, in order to determine the reasonable type of laminated plate, the material budget analysis of assembled laminated plates with different structural forms is carried out. The conclusions are as follows: PK prestressed concrete composite slab has great advantages in the whole material budget cost, which is suitable for all kinds of span buildings. One way steel truss slab and YH prestressed concrete composite slab are suitable for small span buildings.

The concrete-filled fiber-reinforced polymer tube (CFFT) is a unique structural element that is well suited for reinforced concrete applications in harsh environments due to the corrosion-resistant reinforcement. It also benefits from the stay-in-place formwork capabilities of the reinforcement and the beneficial concrete confinement offered primarily in cases of axial compression. The strength and response of the CFFT system have been studied under axial, flexural, and combined loading conditions; however, its torsional behavior has not been evaluated. Some of the challenges have been the ability to provide successful gripping of the circular cross-section as well as avoiding the undesired second-order effects when pure torsion is investigated. This paper presents a novel apparatus developed to test circular members, including CFFTs, to failure under a variety of loading conditions including pure torsion, and combined torsion, bending, and axial compression. The apparatus can accommodate a complex set of geometric nonlinearity effects associated with the deformations arising from multiple degrees of freedom. The functionality of the testing system under a state of pure torsion and combined loading was verified. The results showed that the testing apparatus effectively simulated the intended loading condition. The samples experience relatively large and complex displacements that justified the details incorporated in the design of various components of the testing configuration.

TRC permanent formwork is made of a new type of cement-based material and has wide application prospects in formwork engineering. To promote the large-scale development of TRC permanent formwork and make it widely used in engineering practice, based on the single-lap shear test, this paper analyses the bonding properties between the TRC permanent formwork and cast-in-place concrete at different lengths in terms of the failure mode, load-slip curve, etc., and further elaborates on the fracture mechanics theory. The research shows that when the length of the formwork small, the failure mode of the specimen measured by the single-lap shear test mainly occurs at the textile-matrix interface in the TRC permanent formwork; when the length of the TRC formwork large, the failure mode begins to change to textile fracture. The effective bonding length of the TRC permanent formwork and the cast-in-place concrete is approximately 150 mm. When the TRC formwork length is less than 150 mm, the interface bonding force increases continuously with increasing TRC formwork length. The load-slip is mainly divided into two curves with typical characteristics. The first type of curve has a clear load softening stage, and the whole curve of the second type has a stage where the slip increment is small and the load drops sharply. Finally, the interface fracture energy can better characterize the interfacial bonding properties between TRC permanent formwork and cast-in-place concrete.

In order to avoid the shortcomings of the traditional building template, such as the cumbersome process of supporting and disassembling the mold, the low turnover, and the occupation of a lot of labor, it is proposed to replace the traditional building formwork with the textile reinforced concrete (TRC) as a permanent formwork. In this paper, the template form is used as the research parameter, and the bending performance of the U-shaped and single-plate TRC template composite beam and the comparative beam under static load is compared and studied. The test results found that during the loading process, the single-plate formwork composite beam was peeled off from the TRC formwork, and the U-shaped formwork and the post-cast concrete interface bonded well. Under the premise that the interface between the formwork and the post-cast concrete is good, the cracking load, yield load and ultimate load of the TRC formwork composite beam are improved compared with the ordinary reinforced concrete beam; the crack width of the composite beam is smaller and the development is slow; Bending rigidity becomes greater but ductility is reduced to a certain extent. Overall, the bending performance of the U-shaped formwork composite beam is better than that of the single-plate formwork composite beam. In addition, on the basis of the test, this paper puts forward the formula of the normal section bending capacity of the U-shaped TRC template laminated RC beam, and the test results are in good agreement with the theoretical calculations.

In fiber-reinforced polymer-stay-in-place (FRP-SIP) system, the FRP is structurally integrated with concrete to use as a permanent formwork that also provides tensile reinforcement to the member. The present work investigated, experimentally and numerically, the complex behavior of FRP-SIP composite system with a commercially available pultruded glass FRP section as permanent formwork. Beam and slab specimens were prepared in the laboratory with the glass FRP as permanent formwork. Flexure tests were carried out in order to understand the influence of FRP as a stay-in-place member on the load–displacement response and failure modes of the system. It was observed that the beams under flexural loading had improved flexural capacity due to FRP-SIP and failed predominantly in shear mode. Along with shear failure, delamination of the FRP was also observed in some cases. The results revealed that FRP-SIP system was capable of providing adequate flexural reinforcements to the concrete structural members and thus showed the ability of replacing steel reinforcements. A three-dimensional finite element (FE) model was developed for the FRP-SIP concrete, which was capable of capturing the multifaceted behavior of the composite system. The FE model was validated with the experimental results of the present work and also with that obtained from the literature.

This study was conducted to develop a corner-supported auto-climbing formwork system (CS-ACS) that uses steel plates installed at the corners as support points in connection with the development of...

Concrete filled steel tubular (CFST) members has its successive footprints in the construction industry, owing to its high load carrying capacity, improved ductile performance, large energy absorption capacity etc. CFST column has its own advantages like maximizing the useable floor area and minimizing the need of formwork. In this research work, experiments are carried out on 8 circular CFST columns with 60 mm diameter and 2.5 mm thickness. The parameters varied are height (960 mm, 900 mm, 840 mm and 750 mm) and the in-filled materials like normal strength concrete and high strength concrete. The study mainly focused on analysing the codal provisions like Eurocode4, ACI and AS codes with the experimental results. From the study, the influence of slenderness ratio over effect of confinement is observed and evaluated. As the codal provision seems to be too conservative in predicting the compressive behaviour of CFST columns, a modified approach is derived. The analytical expression predicted by this simplified method is applicable for CFST columns with L/D ratio varies from 13 to 16.

SCC (Self compacting concrete) is the concrete which can flow in to the entire form work and de-aerated entirely and consolidate by its own self weight. Due to its cohesiveness, it can fill the pores of concrete at any shape and size without bleeding and segregation. This property makes, SCC to use in highly/congested reinforcement presence to pour it on/between the formwork. SCC has been found in Japan, to construct the girders, towers, piers, Liquefied Natural Gas (LNG) tanks, culverts and building structures. In precast concrete industry, the usage of SCC is high where the vibration is not required. This research work concentrates on making SCC with steel fibres for the mix design of M30, M35, M40, M45, M50, M55 and M60. As per the European Federation of National Associations Representing for Concrete (EFNARC) guidelines provided for the SCC, the concrete undergone for its fresh concrete properties tests and satisfied the requirements also the compressive strength, split tensile test and modulus of rupture test on the standard specimens were performed to find its mechanical property with and without fibres. The fiber reinforced self compacting concrete (FR-SCC) has performed well when comparing to the conventional specimen.

Formwork has become wide spread which uses moulds made up of timber or steel in construction. In this research we have used a sensor to find the lateral pressure on formwork which will be cost effective and ensure efficient utilization of materials concerning its loads and deformation. A vertical column formwork is casted and concrete is poured at different intervals of height. At various level of rise of concrete and at various height and also during the setting of concrete the pressure on formwork was recorded in a sensor device and it is compared with theoretical pressure obtained from CIRIA formula.

Purpose. Improvement of the technology of laying a ballastless bridge deck on BMP slabs by replacing wooden gaskets with fast-hardening high-strength pouring mixtures with the installation of the slabs in the design position using special control devices. Methodology. A regulating device proposed by the authors, consisting of a BR-type bolt and an embedded part, which is part of the slab of a ballastless bridge deck. The device ensures the installation of the BMP slab in the design position vertically with an accuracy of ±1 mm and withstands the load from its own weight and the rolling stock used in the laying and straightening of the bridge deck. For laboratory tests, a scheme was developed and a stand was built, which allows, in accordance with the requirements of U 7012.02.000 PM (2012), to carry out the load on the BMP-KRm plate installed on the regulating bolts of the BR type. The load was provided by a hydraulic system and transmitted to the plate through track rails mounted on the plate, applied at two points on each rail symmetrically about the longitudinal axis. The tests were carried out until failure. Results. With a load of 137 kN per point, there was a loss of stability of control bolts of the BR type. A fixed formwork and a fast-hardening non-shrinking mixture were used instead of spacers in cooperation with regulating bolts of the BR type. Originality. It consists of obtaining the dependences of forces on the design of the BMP. Practical value. The accordance of prototypes of plates of the BMP-KRm type with elements of regulation of their design position to the requirements of design and technical documentation was confirmed.

Flat slab is reinforced concrete plate construction without beam. Without using beam, the obtainable profit is to minimize concrete volume, height/floor, and structural load. Other profits are simpler and economic reinforcement, scaffolding, and formwork. In this study, structural redesign of RSGM UGM Prof. Soedomo Yogyakarta building was made by using flat slab method. The objective of this study was to find structural dimension of floor and roof plates as well as reinforcement of the RSGM UGM Prof. Soedomo Building using structural system of flat slab, dimension of structural column and drop panel as well as reinforcement of the RSGM UGM Prof. Soedomo Building using structural system of flat slab. This method was to redesign using flat slab method complying with the standard of SNI 2847-2013 and software ETABS 2017. The results of analysis and calculation of structural dimension using flat slab method showed floor plate thickness of 170 mm; roof plate thickness, 120 mm; drop panel thickness, 270 mm with drop panel width of 2000 mm in direction x and 1500 mm in direction y, as well as use of column dimension of 500 mm x 500 mm. The analysis using software ETABS 2016 showed building structure in period (T) of 1.07 seconds.Keywords: RSGM UGM Prof. Soedomo Building, Drop Panel, Flat slab.

The large-span ice composite shell structure constructed by inflatable formwork and cellulose-water mixture spraying method brings a new aesthetic activity to the conventional ice and snow buildings. How to ensure the structural safety of large-span ice shells and satisfy the serviceability in the operation stage has become an urgent problem for structural engineers. Based on the Koi-fish ice shell structure constructed in winter at Harbin Ice-Snow World, China, exhaustive structural investigations on the behaviour of the ice composite shell under multiple load conditions are conducted. Subsequently, the construction quality of the ice shell after completion is discussed and evaluated. The results show that temperature action is the main factor affecting the structural safety of the ice shell. Construction assessment results show that the practical ice shell structure can satisfy the design safety requirements.

Concrete significantly contributes to carbon emissions and ever growing need for infrastructure consequently demands an increase in this consumption. Ergo, making the reduction of concrete consumption a challenging task. This challenge can be tackled by nature driven approaches, which provide an intuitive strategy to achieve efficient structures with reduced volumes. In this research, parametric assessment of catenary shaped fabric-formed concrete beams was conducted. Bezier spline was used to frame the longitudinal profile with mid-span depth ( d c ), support depth ( d s ) and breadth (b) as guiding parameters for the overall topology of the beam forms. Fabric formwork manufacturing approach was employed, given the hanging nature of the topology of resulting beam forms The main objective of this investigation was to assess the structural response of these beams at various parametric cross-sectional variations with d c to d s ratio as 2:1. All beam specimens exhibited a flexural response hence signifying the efficacy of 2:1 ratio. Moreover, higher d s / b values exhibited an extended plastic phase. Whereas, an increase in volume prediction error was recorded as a result. Response surface methodology model equations predict elastic and plastic failures to an accuracy of about 85%.

The Extended Limit Analysis of Reinforced Masonry (ELARM) is a simple and user-friendly method for the design and structural analysis of singly-curved, reinforced tile vaults [1]. It is based on limit analysis but takes into account the reinforcement’s contribution to the composite cross-section’s bending capacity. A three-dimensional approach to ELARM is presented in this paper. The theoretical framework to understand the implications and limitations of extending ELARM to fully 3D structures is described, together with the strategies to carry out the leap from 2D to 3D. This extension is a lower-bound approach for the design of reinforced masonry, reinforced concrete and concrete-masonry composite shells and the assessment of their strength and stability against external loading. The new, extended method is implemented computationally to speed up the iterative processes, provide quick structural feedback, offer immediate results and allow for user-interactive form-finding and optimisation procedures. Different applications of the developed tool are described through the presentation of examples, including reinforcement optimisation, a form-finding process and a case with a shape beyond funicular geometry. [1] D. López López, P. Roca, A. Liew, T. Van Mele, P. Block Tile vaults as integrated formwork for reinforced concrete: Construction, experimental testing and a method for the design and analysis of two-dimensional structures Eng Struct, 188 (2019), pp. 233-248, 10.1016/j.engstruct.2019.03.034, Structures, 35, ISSN:2352-0124

Ultra-high-performance concrete (UHPC) is already gaining in-field applications in bridge deck rehabilitation. On the other aspect, an innovative NC-UHPC composite deck system was motivated to promote accelerated bridge construction (ABC) implementation of a newly built bridge, of which the precast UHPC substrate serves as the formwork for the cast-in-place NC overlay. Performance characterizations were investigated by loading five decks, of various UHPC thickness and w/wo longitudinal or transverse rebars. Their effects on the composite decks’ failure patterns and load-deflection curves were quantitatively analyzed. Besides, digital image correlation (DIC) technique was adopted to adequately capture their damage evolutions. Moreover, analytical solutions for predicting a composite deck’s flexural and shear strengths are tentatively derived. Finally, 3D finite element (FE) models are developed within ATENA framework, capable of embracing the NC-UHPC interface’s behaviors. Numerical predictions agree well with the experimental results and can benefit further researches evolving a NC-UHPC composite deck system.

At present, the construction of frame buildings is carried out on ordinary pillar foundations, the device of which is associated with the need to carry out a large amount of excavation, significant costs for the manufacture of formwork and preparation of concrete mix in cramped conditions. Reduced labor costs and savings can be obtained by using foundations from bored piles and the installation of reinforced concrete grouting, and this also requires fragments of pits, additional outlets of reinforcement, waste of materials. In addition, concreting of grillages with a technological break after the installation of piles increases the construction time. More economical is the use of single drill support columns. They have a larger trunk diameter than brown stuffed piles and higher bearing capacity. The extensions at the top of the trunk increase the ground resistance in the horizontal direction due to the developed lateral surface, and also favors the use of vertical loading to load the vipore prism, which is adjacent to the upper part of the support (by analogy with pyramidal piles). Expanded plate raises the bearing capacity on the ground to the effect of vertical loading. The increase in industrial and civil construction and the need to design reliable and economical structures require the development of modern forecasting methods for determining the bearing capacity of this type of foundations in order to ensure the strength of structures. The development and implementation of more advanced and economical methods of calculating and designing foundation structures aimed at the development and implementation of their reserves is an important and relevant problem of building science. Taking into account the nonlinearity of the deformation of foundations in conjunction with the principles of their optimal design allows us to increase the adequacy of the calculations and obtain a significant economy of concrete and reinforcement. In the work on the numerical method of boundary elements (SEM) from the positions of the mechanics of a dispersed elasto-plastic medium, the concepts of predicting the bearing capacity of drill columns with extensions in the upper and lower parts are laid out. The solution of the nonlinear problem of predicting the bearing capacity of drill-pillars with extensions is of both scientific and practical importance and is directly related to the analysis of the ground VAT.

To reduce the density of bamboo-based concrete formwork on the premise of meeting the performance requirements, the bamboo was first treated by cold plasma, and then by increasing the distance between the adjacent bamboo strips of the radial bamboo curtain in the middle layer, the internal porosity was increased. The production of lightened bamboo based concrete formwork, which meets China’s forestry industry standards, was achieved. Four groups of bamboo-based concrete formworks with different slab structures were designed. The key results showed that slab structures have an extremely significant effect on the density, MOR, MOE, IB, and TS of the bamboo-based concrete formwork. A group of optimal slab structures was obtained by comparing their physical and mechanical properties (1st and 9th floor-phenolic resin impregnated paper, 2nd and 8th floor-bamboo mat, 3rd and 7th floor-tangential bamboo curtain, 4th and 6th floor-radial spaced bamboo curtain). Based on the required physical and mechanical properties, its density was 0.62 g·cm-3, which was 27.1% lower than that of traditional bamboo plywood template (0.85 g·cm-3) circulating on the current market. This lightened BBCF can save raw materials, facilitate transportation and reduce labor intensity in the application process so that it will be widely used in building construction.

The timber board interlayer is applied as the formwork for the pouring of concrete slab in various practical applications of timber–concrete composite structures, with the rehabilitation of timber buildings, in particular. At present, there are few studies performed to study the shear stiffness of inclined screws in timber–concrete composite beams with timber board interlayer. In this article, eight groups of shear tests were carried out to study the shear stiffness of inclined screws in timber–concrete composite beams with timber board interlayer. The key parameters included the embedment depth of the screw connector into timber, screw diameter, the thickness of concrete slab, and concrete strength. As indicated by the test results, the shear stiffness of the inclined screws was improved as the embedment depth of screw into timber and screw diameter increased. When the embedded depth of screw into concrete remained unchanged, the thickness of concrete slab and concrete strength exhibited no significant impact on the shear stiffness of inclined crossing screws. On the basis of the theory of a beam on a two-dimensional elastic foundation, the calculation method for predicting the shear stiffness of inclined screw in timber–concrete composite beams with interlayer was proposed. The comparisons demonstrated that the shear stiffness of inclined screw can be well predicted using the calculation method.

One of the most important components in the construction execution is concrete works. Therefore, we need formworks to form the structural elements that are planned in a construction process. In the process, an economical alternative needs to be taken regarding choosing formwork material to get more benefits, both in terms of cost and time. Fabric formwork can be an alternative solution for formwork material. An example of a feasible formwork material alternative is woven polyethylene-based formwork. The purpose of this research is to evaluate the performance value of woven polyethylene formwork and compare it with the conventional formworks such as wood and brick in terms of cost and time. Field observations and literature reviews have been done to answer these questions. By using woven polyethylene formwork on tie beam and pile cap structure, it was found that the average time and the investment cost of installation are consecutively 344.23 s/m2 and IDR75000 which is faster and cheaper than using conventional ones.

Providing web opening in the shear-span zone of RC beams results in significant reduction in the shear capacity of such beams. Thus, an efficient restoration technique has to be found out and implemented in order to compensate the developed reduction. The main target of the current paper is to introduce and validate an innovative restoration technique for the new construction making use of the Strain-Hardening Cementitious Composites (SHCC) material. Accordingly, precast thin SHCC plates having the required opening were cast and cured for about 3 weeks to eliminate the volumetric change issues, and then placed inside the formwork at both sides before casting the RC beams included web openings. The chosen thickness of the SHCC plates was 20 mm in order to be easily accommodated in the concrete cover. For the considered openings, the opening depth was kept constant to be 0.30 of the beam effective depth, while the opening length was varied considering three values; 150, 300, and 450 mm. Besides, small amount of internal reinforcement in the form of steel wire mesh was provided inside some SHCC plates in order to enhance their shear strength and ductility. Experimental results showed that the provided SHCC layers enabled the strengthened beams to exhibit distinguished performance in terms of ultimate capacity, ductility and decreased shear crack width. In addition, the gain in shear capacity due to the SHCC plates is decreased with the increase of the opening width. Finally, comparisons between the obtained experimental results and the predicted shear capacities stipulated by the ACI 318-19 and JSCE codes were performed. The comparisons revealed that the estimated shear capacities are in satisfactory agreement with the experimental results, however, these estimations tend to be overestimated with the increase of the opening length.

Rammed earth (RE) is a sustainable material which is made by compacting the soil in a formwork. The earthquake performance of RE structures is an important topic, however the out-of-plane seismic behavior of RE structures has not been thoroughly investigated in the literature. The objective of the present paper is to study the out-of-plane seismic behavior of RE walls by using finite element method. The model used involved the concrete damage plasticity (CDP) model to simulate the nonlinear behavior of the earthen layers, a surface-based cohesive behavior to simulate the linear and nonlinear behavior of the interlayers (between the layers). The parameters of the model were first validated through the simulations of available experimental tests in the literature for both in-plane and out-of-plane loading. Then, a U-shaped RE wall was modelled which was composed of one longitudinal wall (4.6-m-length × 2.4-m-height × 0.5-m-thickness) and two transversal flanges (2-m-length). Effects of the bond beam (on the top of the walls), the interlayers and different earthquake amplitudes were studied. The results showed that the implementation of the interlayers in the model had clear influences on the ultimate load and the failure modes but the inter-storey-drift was few affected; the bond beam played an important role for the out-of-plane seismic behavior of the RE wall. The performance of the studied RE structure was satisfying until a seismic amplitude of 0.223 g.

The Upper Longitudinal Beam casting on the Jabodebek LRT Project requires a shoring to be able to withstand the workloads. To avoid the failure of formwork construction, formwork must meet the strength, stiffness, and stability requirements for each formwork component material. The analysis is carried out on the value of bending stress, deflection, and shear that occur in each component of formwork. From the analysis carried out each obtained as follows. Strength requirements with flexural stress values that occur in Plywood, Girder GT 24, and Steel Waller SRZ materials, each of which is smaller than ? permit = 100 kg / cm2, 70000 kg / cm2, and 1200 kg / cm2. Stiffness requirements with deflection values that occur on Plywood and Girder GT 24 material are ? permit = l / 400. Whereas the SRZ Steel Waller fulfills ? permit = l / 240. Stability requirements with shear stress values that occur in Plywood, Girder GT 24, and Steel Waller SRZ materials, each of which is smaller than ? permit = 12 kg / cm2, 1400 kg / cm2, and 696 kg / cm2. Peri Up Shoring can support all formwork loads. So it can be said that the construction of the Upper Longitudinal Beam formwork is in a safe condition.

Steel concrete composite columns are widely used in high rise buildings and bridges. Composite columns provide not only great reduction for the column size and weight, but also high columns efficiency and ductility. In Concrete Filled Steel Tube (CFST) columns, the steel tube provides formwork for the concrete; the concrete prevents local buckling of the steel tube. This paper illustrates a theoretical study of the behavior of CFST columns subjected to centric load by using ANSYS (18.1). The study divided into two parts. In the first part, the verification of the program was done using an experimental work of previous research, this verification showed that the capability of ANSYS program for analysis of the CFST columns with very good accuracy. In the second part: a parametric study was carried out to study the behavior of CFST braced, constant cross section area, centric loaded columns. The main variables were the shape of cross section (three shapes: square, rectangular and circular) and slenderness ratio (λ). The analysis shows that the increase of the slenderness ratio led to decrease the ultimate load capacity, stiffness and ductility of the CFST columns. The current ECP of concrete code underestimates the values of ultimate load capacity while, ECP of steel predicts the reasonable values for an ultimate load capacity of CFST columns.

The reinforced concrete slab is a universally accepted technology for roofing and flooring systems. In fact, in recent times, villagers in India have enthusiastically taken to reinforced concrete instead of tiled roofing. However, there are some disadvantages of RC slab which affects its affordability and ecological soundness. The problems may be listed as follows; (a) In RC slab of 12.5 cms thickness, the bottom portion of 6–7 cms will be under tension. Hence, the concrete using a high cement content remains cracked and ineffective. Its only function is to provide a good lever arm between the steel and the centre of compression. (b) Secondly, the in situ nature of concrete slab construction needs an elaborate and time consuming formwork to support the fresh concrete. (c) When the RC slab is used as a roof it picks up a lot of solar heat and radiates it into the interior for several hours after sunset. This can be especially problematic in hot and dry areas. An alternative to the RC slab must explore ways of replacing expensive concrete at the bottom by a less expensive and insulating material. The problem of formwork has to be solved by looking at partial or completely prefabricated components. This study deals with such a solution which may be named as the composite T-beam.

Semi-precast-reinforced concrete slab system offers more economic method of construction as it minimises the need of formwork at site. The assembly of semi-precast slab system involves two steps: (1) casting of semi-precast slab at the yard and (2) overtopping of concrete at the site. One of the main factors that influence the performance of such slab system is the interface bonding between precast and overtopping concrete. Therefore, in order to better understand the performance of this slab system, a research was carried out to investigate the influence of surface treatment methodologies to the overall flexural behaviour through experimental and numerical studies. In total, five representative semi-precast slabs were constructed and tested to assess the flexural performance with different surface preparation methods and concrete overtopping. Further small-scale precast with overtopped concrete couplets and triplets were casted and tested as the representative semi-precast concrete slab types to examine the interface shear and tensile bond strength characteristics with those different surface treatments. The experimental results revealed that the surface treatment methods have influenced the flexural behaviour of the slabs, where the interface shear bond strength exceeds more than 1.0 MPa and the slab system behaves monolithically under flexural action. Moreover, numerical modelling technique for this slab system was developed based on the finite element framework to further analyse the overall flexural behaviour. Subsequently, good agreements between experimental and developed numerical model results were found. Finally, parametric analyses were performed to further assess the influences of concrete strengths, spans and reinforcement ratios on the safe imposed pressure applicable for this slab system.

Shallow wide beams in structural systems are a good solution for many architectural constraints. In addition, these beams give construction time saving because of the simplicity of formwork and rei...

This study is trying to provide an economic form of a reinforced high strength concrete beam used for a bending moment load, by replacing a quantity of the high strength concrete with normal concrete. Normal concrete will be used in the tension zone and the high strength concrete in the compression zone of the beam, in order to optimize the behavior at bending moment and to highlight the economic benefits. The formwork was established following a parametric study to obtain a minimum amount of high strength concrete in the beam, compared with a reinforced concrete beam composed integrally of high strength concrete using the same loads. Different types of concrete delimitation was made after a flexure design to obtain a minimum ratio between high strength concrete and normal concrete.

The article emphasizes the importance of developing the Arctic and reveals the existing problems of construction in this zone. The existing methods of construction of quick-assembly structures, including the use of pneumatic formwork, are analyzed. A crane-free technology for the construction of a domed building using pneumatic formwork is proposed, with subsequent filling of the inter-deck space with foam material based on Quad Core.

The design of the formwork support for a certain section of the Beijing subway project was carried out in this paper. And the disk lock formwork support was used in the engineering.It was analyzed on the the design of the formwork support for the roof with the thickness of 1.5m of the interval engineering. The manual calculation and the sap2000 finite element analysis were also used in the paper.The effect of the diagonal brace and its number were analyzed in addition to the design of the formwork support. It was showed that the axial force of the standing tube tends to be uneven with the increase of the number of slant bars in the framework. And the axial force of the standing tube connected to diagonal brace is larger than that of the framework without brace significantly. So it will be dangerous to the framework without considering the effect of it by the manual calculation.

Concrete is most widely used in the construction industry and now-a-days Self compaction concrete is used because of its easy flow able properties and reduction in construction time. Self compacting concrete (SSC) is a basic type of concrete that does not required any kind of compaction or vibration. SCC was first developed by Okamura in Japan during the year 1980. This type of concrete flows easily around the reinforcement and into all corners of formwork and also it saves time, labor and energy. Different admixtures are used to produce effective self compacting concrete (SCC). The workability characteristics of SCC will be evaluated by the following tests like Slump Flow, V- Funnel, L-box Test. Many researches were carried out around the world with regards to different applications on properties and mix proportions. This paper includes the literature reviews related to behavior of self compacting concrete also deals with the strength and behavior of self compacting concrete using fibrous materials and mineral admixtures.

The study of the early-age behavior of Timber-Concrete Composite (TCC) structures is of great interest as it provides valuable information for manufacturing specification development, quality control, and optimization of the formwork design. In this study, the results of the continuous monitoring of the short-term behavior of TCC slabs using Brillouin Distributed Optical Fiber Sensors (DOFS) are reported. Two TCC slabs with 8.5 m of length were monitored. The composite elements are constituted of Cross-Laminated Timber (CLT) connected to a High-Performance Concrete (HPC) slab. During a monitoring period of about 30 days, the early-age temperature/strain variation in the fresh concrete and in the CLT slab was measured in great details by DOFS. From the presented results, the significant influence of the curing conditions on the early-age shrinkage was highlighted. It was also observed that creep and the daily hygrometric variations of environment affect considerably the composite action between the timber and the concrete. In addition, it was experimentally demonstrated that such mechanisms generate considerable structural changes in the composite elements even before their entry into service.

Double skin composite (DSC) construction or Steel/concrete/steel sandwich construction (SCSS) is an innovative and relatively new form of composite construction that can be used in submerged tube tunnels, bridges deck, nuclear structures, liquid and gas containment structures, offshore and onshore structures, military shelters, and shear walls in buildings. The system consists of a plain concrete core sandwiched between two steel plates interconnected together by various types of mechanical shear connectors. The DSC construction perceives advantages that the external steel plates act as both formwork and primary reinforcement, and also as impermeable, blast and impact resistant membranes. The major duty of the shear connectors is to withstand longitudinal shear force and beam/slab separation, while in the bi-steel type where shear connectors are friction welded at both their two ends to two parallel steel plates, the longitudinal and transverse shear force, as well as plate buckling are resisted. The present paper highlights the previous prime researches concerning the subjects of SCSS composite construction, specifically on the conducted tests (push-out tests, tensile, direct shear tests, and bending tests) in which the components of partial interaction (uplift and slip forces) are resisted by various types of shear connectors.

The paper presents an estimation of the optimum cost of an isolated foundation following the safety and serviceability guidelines of Indian Standard (IS) 456:2000. Two adaptable optimization algorithms are developed for the first time to optimize the cost of any type of isolated footing design. Two optimization methods, i.e., constrained binary-coded genetic algorithm, with static penalty function approach and unified particle swarm optimization are developed in MATLAB compliant for optimal design of any isolated foundations. The objective function formulated is based on the total cost of footing. This includes the cost of concrete, the cost of steel and cost of formwork. The design variables which influence the total cost of footing are plan area and depth of footing and area of flexural reinforcement at moment critical sections. The footing design algorithm is developed according to the biaxial-isolated rectangular footing as per IS codes. The constraints, e.g., dimension of footing, restriction on bending, shear stresses and displacements, are considered in the footing design algorithm which acted as a subroutine to the developed optimization programs. Four different numerical examples have been solved to evaluate the versatility of the developed method. A comparison study has been done to observe the efficacy of both the optimization methods.