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Vector II slab was tested on a natural scale (a slab with a dimension of 6.30 × 6.30 m) and a strip 6.30 m long and 1.20 m wide. The Vector II slab is built by precast panel 60 cm wide, 4 cm thick and 14-20 cm thick concrete overtopping on the construction site. The main purpose of the slab tests on a natural scale was to observe the “faulting” effect and temporary deflections. During the tests, the displacements in the area of the panel joints in the middle of the slab span were recorded. The maximum difference in displacement between adjacent panels of the slab model was 0.16 mm, and the vertical displacement was 1.9 mm. The strip model had no cracks that could indicate a interface cracks between the precast element and the concrete overlay. After completion of the field tests, the load was left on the slab model to verify long-term effects.

Concrete structures have been widely used for many years to resist impact loads. Steel–concrete composite structures may be considered efficient structures in the emerging modern construction field. Hence, the main objective of this research was to study the impact behavior of steel concrete composite slabs with different shear connectors and compare them with conventional slabs. Seven specimens of dimensions 500 × 500 × 50 mm were cast, which included plain cement concrete slabs, two reinforced cement concrete slabs with steel mesh and steel rebars as reinforcement, and four steel-concrete composite slabs with four different shear connectors: stud, tee, angle, and channel connectors. The composite action was achieved using a steel decking sheet welded with connectors on which the concrete layer was poured at the top. The test setup was fabricated with slots provided for specimens with simply supported end conditions and a mild steel drop weight. The specimens were impacted at the center of the span by dropping a steel mass from a free fall height of 1 m. The number of blows corresponding to the initial cracking and ultimate failure stages was recorded. The parameters that were used to compare the specimens were the impact energy absorbed, crack pattern, crack width, and increase in impact energy from the first blow to the last blow. The experimental results were very close to the analytical results obtained using ANSYS. The experimental and analytical results showed that the composite slabs with channel connectors performed better than the others, and it was proven that the composite slabs performed better under impact loading than conventional slabs.

Cracks that occur in rigid pavements include longitudinal cracks, transverse cracks, and corner cracks. The relatively large crack width not only spoils the aesthetics of the concrete structural elements but can also lead to structural failure. This study aims to determine the crack width of a rigid pavement concrete slab located above the subgrade which is considered a beam on an elastic foundation, so that a minimum rigid pavement concrete slab thickness can be recommended. The specimen will be observed at various thicknesses to obtain the optimum thickness. The load used is a centralized monotonous load, which represents the load of the truck vehicle. The research limitation is using a test object in the form of a concrete plate measuring 2000x600 mm which is placed on the ground with CBR=6 %. The quality of reinforced concrete slabs is fc'=40 MPa and fy=440.31 MPa. The thickness of the concrete slab varies between 100 mm, 150 mm, and 200 mm. The slab placed on the ground is then given a central loading in the form of a centralized monotonic load. The loading range starts from a load of 2–180 kN with a load interval of 2 kN. The experimental results show that the rigid pavement slab has a bending failure so that the crack pattern that occurs begins with the first crack on the underside of the slab. The crack pattern in terms of slab thickness variation has a similar pattern. The initial crack width on the slab is 0.04 mm. The thicker the slab smaller the crack width at the same load. Based on the maximum allowable crack width=0.3 mm. For loads between (80–100) kN (Road Class I, II, and III), a minimum thickness of rigid pavement slabs (70–80) mm is recommended. For loads between (130–140) kN, the minimum thickness of the rigid pavement slab (105–115) mm is recommended

The structural assessment of doubly-curved vaulted masonry structures, such as pavilion vaults, poses challenges specific to their high degree of indeterminacy. Two-dimensional equilibrium analysis methods may provide a lower bound of load or displacement capacity, but they do not accurately describe the three-dimensional (3D) behaviour of these structures, particularly when shear deformation (e.g. sliding) is important. Therefore, discrete element modelling (DEM) methods, which can effectively simulate 3D load re-distribution, have been used to investigate support displacement capacity and corresponding 3D collapse mechanisms. DEM analyses are usually conducted on perfect digital geometries. Meanwhile, both real structures and small-scale physical models have implicit assembly and fabrication imperfections, which may significantly alter their response. The present paper aims to investigate the influence of geometrical and mechanical imperfections by comparing DEM analyses with the results obtained from tests on a scale model. In particular, a new method to simulate imperfections within the DEM framework is proposed, and a DEM parametric analysis is compared to the measured behaviour of a 3D-printed scale model of a pavilion (or cloister) vault on spreading supports. The influence of both mechanical imperfections and geometrical imperfections, due to element geometry deviations or imprecision of the assembly process, have been investigated. Based on these analyses, the three-dimensional behaviour of a pavilion vault subjected to horizontal displacement of the supports is described, and the variability of results due to imperfections is demonstrated. A good agreement between DEM analyses and 3D-printed scale model tests is achieved, in terms of crack patterns and mechanisms. Geometrical imperfections did change the load paths within the vault, as expected, and also influenced the displacement capacity., Engineering Structures, 228, ISSN:0141-0296

Composites made with inorganic matrix, namely fabric reinforced cementitious mortar (FRCM) composites are becoming widespread as strengthening materials for existing masonry structures. These composites are made of a dry grid of fibres embedded in an inorganic matrix. FRCMs can be considered a valid alternative to traditional organic composites such as fibre reinforced polymers (FRPs) because of their better compatibility with the masonry support. This work presents an experimental study for the tensile characterization of a basalt fabric reinforced cementitious mortar (BFRCM) composite. Tensile tests were carried out on coupons reinforced with one, two or three layers of grid to investigate the influence of the reinforcement on the load–strain and stress–strain response of the composite. The basalt grid and cementitious mortar matrix were also tested in order to compare the mechanical properties of the constituent materials to the response of the composite. The digital image correlation (DIC) technique was used to check in-plane and out-of-plane bending effect, to measure the crack opening and to analyse the crack pattern evolution and failure modes.

The origin of crack patterns in industrial masonry chimneys is investigated. This information is of utmost importance in defining any preservation project, and designing suitable repair interventions. Attention is focused on a 66 m-tall chimney built at the end of the XIX century, which is representative of numerous coeval chimneys of similar geometry. The base and the shaft of the chimney are double-walled: vertical ribs and horizontal diaphragms partially connect the walls of the shaft; the crown is single-walled. Vertical cracks can be observed in the lower part, horizontal cracks in the upper part, and zig-zag cracks in the central part. The structural behaviour of the chimney was investigated by means of finite elements, under gravity loads and thermal variations. Most of the cracks can be explained by thermal effects, if the anisotropic strength of masonry is duly accounted for. Therefore, new cracking phenomena can be excluded, and suitable repair interventions may allow an adequate level of safety to be attained.

This paper aims to experimentally and numerically investigate the flexural behavior of laced reinforced concrete moderately deep beams. The study focuses on the influence of the lacing angle (30, 45, and 60°) and the ratio of the tension reinforcement (0.33, 1.13, and 2.01%). Six beams were fabricated, with a cross-sectional width of 150 mm and a depth of 240 mm, and 1530 mm in length. In five specimens, lacings were employed as shear reinforcement instead of the conventional stirrups. A reference beam was fabricated with conventional vertical stirrups. All beam specimens were subjected to the four-point bending up to failure with effective and shear spans of 1400 and 400 mm, respectively. Compared to the reference beam, laced beams experienced significant stiffness enhancements of up to 43.7%. However, the improvement in the ultimate load did not exceed 10%. The recorded strains in lacings clearly signify the efficiency of lacings in resisting the longitudinal and diagonal tension stresses induced along the flexural and shear spans. Moreover, a nonlinear finite element analysis was performed using ABAQUS, based on which parametric studies were conducted. Parametric studies showed that the ductility was significantly increased with the increase of lacings bar diameter, while the ultimate load capacity was only slightly enhanced.

International audience; In the last few decades, premature deterioration of reinforced concrete (RC) structures has become a serious problem because of severe environmental actions, overloading, design faults, and materials deficiencies. Therefore, repair and strengthening of RC elements in existing structures are very important to extend their service life. There are numerous methods for retrofitting and strengthening of RC structural components such as; steel plate bonding, external pre-stressing, section enlargement, fiber-reinforced polymer (FRP) wrapping, and so on. Although these modifications can successfully improve the load-bearing capacity of the beams, they are still prone to corrosion damage resulting in failure of the strengthened elements. Therefore, many researchers used cementitious materials due to its low-cost, corrosion resistance, and resulted in the improvement of the tensile and fatigue behaviors. Different types of cementitious materials such as; fiber-reinforced concrete (FRC), high performance concrete (HPC), high strength concrete (HSC), ultra-high performance concrete (UHPC), steel fiber-reinforced high strength lightweight self-compacting concrete (SHLSCC), fabrics reinforced cementitious material (FRCM) and so on have been used to strengthen structural elements. This paper summarized previously published research papers concerning the structural behaviors of RC beams strengthened by different cementitious materials. Shear behaviors, flexural characteristics, torsional properties, deflection, cracking propagation, and twisting angle of the strengthened beams are explained in the present paper. Finally, proper methods are proposed for strengthening RC beams under various loading conditions.

The seismic performance assessment of historical masonry structures is still a complex issue in civil engineering. This paper investigates the seismic response of seven masonry churches, which are located in the province of Ferrara (Northern Italy) and suffered extensive damage during the 2012 Emilia earthquake. Different field surveys, which were conducted after the earthquake to collect information on typical damage patterns, provided a preliminary knowledge of utmost importance for developing detailed FE models of the churches and for better understanding the results of advanced numerical simulations. First, modal analyses were performed to have a preliminary insight into the dynamic behavior of the churches. Then, non-linear dynamic analyses with different peak ground accelerations were carried out in order to obtain the damage distribution in the churches and to identify the most vulnerable macro-elements. The results highlighted the influence of morphological and geometrical characteristics on the seismic behavior of the different macro-elements composing the churches.

Recent Italian earthquakes (L’Aquila 2009, Emilia 2012, Central Italy 2016–2017) have shown the high vulnerability of existing and historical masonry constructions to seismic actions. This ...

Three partially pre-stressed interior beam-column sub-assemblages (SI) and two partially pre-stressed exterior beam-column sub-assemblages (SE) made of reactive powder concrete as test specimens were numerically modeled using a finite element program. The objective of this study was to investigate the behavior of the SI and SE numerical models. The numerical model inputs were: material data, details of test specimen dimensions, and test specimen reinforcements. The numerical models were subjected to the same loads as those applied experimentally. The numerical modeling results were hysteretic and backbone curves and stress distribution contours. The numerical model outputs showed good similarity with the experimental results. The stress distribution contours of the numerical models correlated with the crack patterns in the joint zone of the test specimens. The behavior of the SI numerical models differed from the SE numerical models due to various stresses on the beam plastic joints and the joint zones.

On 7th May 1611, the construction of Esfahan Shah mosque started to be a part of the re-modeling of Safavid capital, a building that adopts a glazed bulbous double dome as a hybrid structure of brick and wooden elements. This paper aims to present building techniques, construction process and conservation works of this complex dome through historical evidence and onsite surveying. For these purposes, following a brief history of the building, the paper explores the geometry, morphology and construction sequences. It subsequently addresses the conservation during the last century from Salnameh (1934–36) up to current intervention and their consequences. The paper necessarily illustrates cracks pattern, not only to recognize its causes via their type and geometry but also to address historical performance and structural capacity. According to the objectives, the study of the Shah dome plays an important role to better understand other similar cases. This paper concludes that structural analysis and future conservation could benefit from the achievements derived from historical research, which also allow further understanding of construction techniques., (undefined)

The preservation (in terms of inhibition of failures and collapses) of architectural heritage against horizontal loads (such as earthquakes) requires an accurate assessment of the non-linear response up to failure: to this aim, the use of advanced numerical tools to perform three-dimensional non-linear dynamic analyses is fundamental. This paper investigates the performance (up to the activation of local failures and under horizontal loads) of three historical masonry palaces of the outstanding cultural heritage in Mantua (Northern Italy) after the 2012 Emilia earthquake. Despite the unquestionable importance of the three case studies, until now these palaces have not been studied with advanced numerical simulations; moreover, the recent seismic sequence and the consequent significant cracks patterns observed in the post-earthquake survey phase have pointed out their vulnerability even to small seismic actions. The first part of the study was addressed to an accurate knowledge of the three palaces, focusing especially on the information gathered during on-site surveys, bibliographical and historical research: the data collected were employed to detect the complex three-dimensional geometry of the palaces under study and to define the cracks patterns. In the second part of the study, detailed and representative three-dimensional finite element (FE) models of the structures were developed and non-linear dynamic analyses were carried out to obtain a deep numerical insight into the seismic response of the three palaces, identifying the most vulnerable elements for each structure. The comparison between the numerical results and the damage survey showed that the numerical approach used in this study may be an adequate tool to properly evaluate the seismic response of historical masonry buildings. A comparative assessment of the results obtained for the different palaces was performed in terms of predicted damage distributions, energy density dissipated by tensile damage and maximum displacements registered for the different macro-elements.

This paper investigates the seismic response and partial failure mechanisms of the Castle of St. George, one of the most renowned monumental constructions of the invaluable cultural heritage in Mantua (Northern Italy), which was hit by the 2012 Emilia seismic sequence. The first part of the study is based on historical analysis, documentary research, photographic collection and field surveys to achieve an accurate knowledge of the castle and a proper evaluation of the damage caused by the earthquake. All the collected information is used to create a representative and detailed finite element model of the castle and non-linear dynamic analyses are carried out using a damage plasticity model with different softening behavior in tension and compression for masonry. The finite element simulations provide additional information on the seismic response of the castle, identifying the damage patterns and the most vulnerable parts for different seismic intensity levels. The numerical results indicate that the corner towers and the vaults are the most damaged elements of the castle. The towers exhibit a severe damage concentration in the battlements, near the enlargements of the section in correspondence with the corbels and along the body near the openings. Moreover, the interaction between the tower and the adjacent walls, which are characterized by a different dynamic behavior, causes marked vertical cracks along the walls in correspondence with the connection regions.

This study presents the performance of a combined finite-discrete element method for prediction of the structural response of reinforced concrete beams under impact loading. A combination of finite and discrete element methods enables the modelling of the concrete and the reinforcement before the concrete cracking, as well as a discontinuous nature of the concrete caused by fracture and fragmentation under high impact loading. Discretisation of the concrete with triangular finite elements is coupled with one-dimensional reinforcing bars embedded inside the concrete finite elements. The cracking in the concrete activates the joint elements used to simulate the non-linear behaviour of both concrete and reinforcement. Numerical analysis based on experimental test data has been carried out to simulate the main features of the reinforced concrete beams impacted by free-falling drop-weights. A high level of accuracy was demonstrated in various comparisons between the experimental tests and the analysis results, including peak displacement, crack pattern, damage level and failure modes of reinforced concrete beams.

The architectural heritage was severely damaged by the seismic sequence that occurred in Emilia (Northern Italy) in May 2012. This paper investigates the seismic behavior of three masonry churches that were damaged by the 2012 Emilia earthquake. The analyzed churches are located in the South-East area of the province of Mantua: they are representative of some churches, denoted as “Matildic churches”, belonging to the territorial area between Lombardia, Emilia Romagna and Toscana and built during the Matilde di Canossa domain, between the X and the XI centuries. The study was based on detailed field surveys, in situ tests, visual inspections and existing archives in order to obtain an accurate knowledge of the churches and a proper evaluation of the damage caused by the earthquake. Then, detailed finite element models of the churches were developed and non-linear dynamic analyses with different peak ground accelerations were performed. The numerical simulations provided a deep insight into the seismic behavior of the analyzed churches, identifying the damage patterns and the main collapse mechanisms for different seismic intensity levels. The obtained results appear to be in a good agreement with the damage experienced by the churches during the earthquake. This study can be considered as a first step to assess the seismic vulnerability of the “Matildic churches”, extremely important for their historical and architectural value.

This study aims to investigate the effects of corrosion distribution, specifically non-uniform and localized corrosion, on cracks propagation in concrete. Different corrosion distributions along rebar length were simulated using a sodium chloride pond with various sizes set on the concrete cover, and a direct current was applied to accelerate the corrosion process. The test results showed that the crack pattern is more influenced by corrosion distribution than by concrete cover thickness. The cracking mechanism was analyzed using the Rigid Body Spring Method with a corrosion-expansion model, which utilized a set of experimental data relating to corrosion distribution. The crack patterns are simulated reasonably well. The analysis also indicated that the internal crack pattern is closely related to concrete surface deformation.

This paper presents the experimental study of concrete beams in bending, externally strengthened with Textile Reinforced Cementitious materials (TRC) with varying contact area with the concrete. In order to study the pure influence of the TRC on the concrete substrate, only non-internally-reinforced concrete beams are considered. The crack pattern evolution is monitored with Digital Image Correlation, and the influence of the contact width between the concrete substrate and the external reinforcement is investigated. The results show that the TRC reinforcement has an important crack bridging capacity, and consequently that its application over the full beam width is beneficial for the loadbearing capacity and the limitation of the crack widths of the concrete beam.

The presence of the largest part of World Heritage sites in a seismically-prone area, like Italy, demands always greater measures to protect the most important built heritage, as well as the minor architecture. This requires a constant improvement of the current protocol from the damage survey and the provisional safety measures to the final intervention. This procedure is summarized, briefly, here and additional practical suggestions are given to improve the activities, based on the experience of on-site volunteers during the damage survey after the earthquake that struck Italy in 2016. Basic issues on the recurrent characteristics of historic masonry buildings, that make them often complex constructions with unexpected behaviour, are fundamental in the preparation of the volunteers in surveying damage. This helps in reducing evaluation mistakes and in designing the provisional safety structures aimed at the preservation of built heritage to the extent possible. Some examples of incorrect interpretation of the damage in historic buildings are reported here. In conclusion, only the awareness that it is necessary that a correct understanding of the recurrent or, on the contrary, peculiar, characteristics of a historic building plays a key role in the damage evaluation and in its subsequent protection from further damage.

Digital Image Correlation (DIC) is a full-field contactless optical method for measuring displacements in experimental testing, based on the correlation of the digital images taken during test execution. It is used in several fields of experimental solid mechanics, but its potential application to the characterization of composite reinforcements has not been fully investigated yet. In this paper DIC is used in tensile and bond tests on composite reinforcements comprising different textiles and matrices. Results obtained by two DIC software programs are validated by comparison with displacement and strain transducers. DIC provides additional information on damage pattern (crack location and width) and composite-to-substrate load transfer mechanism (effective bond length and local stress concentrations). It also offers the advantageous possibility of selecting several measurement points after the test, overcoming some drawbacks of traditional transducers. On the other hand, since only on the outer surface of the specimen is monitored, no information is directly available on the textile embedded in the matrix. The combination of DIC and traditional sensors in laboratory testing allows improving the understanding of the mechanical behaviour of composite reinforcements and the identification of their fundamental properties.

A novel lumped stresses network approach for the analysis of the mechanical behaviour of masonry structures is presented. It is formulated through a network of lumped stresses, making use of polyhedral stress functions and a variational approximation of the continuous equilibrium problem. The proposed method allows for modelling masonry structures as no-tension elements and gives, in the case of curved masonry members, the optimised surface through a predictor-corrector procedure and the stress function describing the membrane stress. The given approach offers a useful tool for predicting the crack pattern of unreinforced masonry structures and the associated stress fields. It is validated against some benchmark case studies dealing with a hemispherical dome, a groin vault, a cloister vault and a masonry beam.

The paper is concerned with numerical modeling of corrosion of steel reinforcement in the reinforced concrete. The cracking response of the reinforced concrete beams due to the corrosion effect of the steel reinforcement and due to the load effects was analyzed. The effect of corrosion was simulated by the nonlinear numerical analysis with the FEM program using the 3D model.

Masonry domes represent an important part of the architectural heritage. However, the literature about domes analysis seems less consistent than that referred to other masonry structures. The collapses that have happened in recent years as a consequence of seismic actions or lack of maintenance show the need for detailed studies. Here a limit analysis to evaluate the masonry domes behavior is presented. An algorithm based on the kinematic approach has been developed to evaluate the geometric position of the hinges that determine the minimum collapse load multiplier. The proposed procedure is validated by a comparison with some meaningful cases - the collapse of Anime Sante Church in LAquila, the collapse of San Nicolò Cathedral in Noto, the crack pattern of San Carlo Alle Quattro Fontane Church in Rome, and the analysis developed on Hagia Sofia in Istanbul. The comparison with real cases shows a good agreement between the model results and the phenomenological crack patterns.

Primary load-bearing glass constructions are often subjected to relatively important in-plane loads, transferred through so-called point-fixed connections. The according in-plane load introduction, structural resistance and failure mechanisms have been studied abundantly for axial tensile loading cases, but are relatively unknown for axial compression, in particular when buckling of the compressed component cannot occur. Consequently, stress distributions, resistance and failure mechanisms of small glass specimens subjected to locally introduced axial compression are investigated and presented in this contribution using a coupled experimental and numerical approach. The stress distributions and observed fracture patterns demonstrated that the major failure mechanism was splitting tension: the glass fractured due to high tensile stresses following the compressive stresses. However, the maximal principal tensile stresses at the crack origin were significantly lower compared to the axial tensile loading case. In addition, and in contradiction to the tensile loading case, significant maximal principal compressive stresses were found at the crack origin, leading to the conclusion that the axially compressed glass panels failed due to a complex stress state and not simply to tensile stresses, as is generally assumed in glass design. © 2009 Elsevier Ltd. All rights reserved.

Seven full-scale steel fiber reinforced self-consolidating concrete (SFRSCC) beams were tested to study the effects of macro steel fibers on the flexural behavior of reinforced self-consolidating concrete beams. The major test variables are fiber contents and longitudinal reinforcement ratios. The ultimate load, midspan deflections, steel reinforcement strains, crack width and crack spacing were investigated. The enhanced ultimate flexural capacity and reduced midspan deflection due to the addition of steel fibers were observed. With the increasing of fiber contents, the strain in longitudinal reinforcement, crack width and crack spacing decreased significantly. The possibility of using steel fibers for partial replacement of the conventional longitudinal reinforcement is estimated, which is meaningful for extending the structural application of SFRSCC. A method incorporating fiber contribution to the post-cracking tensile strength of concrete in the flexural analysis of SFRSCC beam is also suggested. Comparisons are made between the suggested model and the fib Model Code 2010 model with experimental data. The results showed that the suggested model can estimate ultimate flexural capacity accurately., National Natural Science Foundation of China: Grants: 51078058 and 51121005.

Underground Coal Gasification (UCG) is considered to be a clean coal technology primarily intended to utilize deep underground (>300 m) coal deposits. In this process, a mixture of reactant gases like air/oxygen and steam are injected directly to an ignited portion of underground coal seam. UCG involves complex interactions of different processes like drying, pyrolysis, chemical reactions and spalling. Spalling is detachment of small coal particles from the coal seam due to interconnection of cracks developed in it. It plays an important role by offering higher surface area to give improved performance. The mechanism of spalling and its characterization are not well understood. Furthermore, there are no well established experimental techniques to measure the spalling rates. This paper studies spalling behavior of a lignite coal, which is characterized by high moisture and volatile matter, and suggests a possible underlying mechanism. The rate of spalling was measured using an experimental setup under the UCG-like conditions. In this setup, a reacting coal block was attached to a load cell and suspended in a UCG-like environment. When the experiments were repeated under similar conditions with different blocks of same coal, it was found that there were variations in the rates of spalling. This might be due to the heterogeneity in coal blocks in the form of originally present fissures or weak regions. A UCG process model was used to explain these experimental results and also to investigate the effect of spalling rate on product gas calorific value. We believe that spalling happens due to formation and extension of cracks. Hence a microscopic crack pattern on a heated coal monolith was examined in different stages of heating to understand the mechanism of spalling. It is concluded that cracks are first formed during the initial stage of drying due to the capillary stresses developed due to removal of moisture from the pores and were further extended due to shrinkage of coal during pyrolysis. The detachment of coal particles happens due to horizontal linking of vertical cracks, which might result out of either horizontal cracks, if any, or available fissures and weak regions or relatively weak interlayer bonding at the bedding planes. (C) 2015 Elsevier Ltd. All rights reserved.

Historic buildings rarely show themselves as they were to their origins, with the same shape and materials The signs of local repairs, but also modifications and expansions are reported on the building as indelible scars that need to be recognized and interpreted. It is important to read these signs, especially in load-bearing structures. One of the first steps for this study is the correct analysis and classification of the quality of the load-bearing masonry, with the help of both an accurate visual inspection and a diagnostic investigation. The classification of the correct masonry typology is now requested also by the last Italian seismic code (NTC 14.01.2008 and annexes), that supplies different mechanical parameters useful for the structural evaluation, according to the masonry typology. Serious mistakes can be made in the structural evaluation of a historic stone masonry if the definition of the masonry typology is incorrect. In several cases there is no coincidence between the visible masonry texture and the transversal cross section. There are different levels of approaching this matter, starting from a description based on a visual inspection, that can be carried out with the help of a template, till the parameters definition achieved by in situ investigation tests. Several parameters may be important to be determined in order to evaluate properly a masonry. The results of the experimental investigation (with a comparison between NDT and MDT tests) and a methodology for the analysis of the masonry quality, according to the standard suggestions for the knowledge levels, reporting all the pros and cons of all methods, are here presented.

Modern technologies of 3D computer modelling with the help of finiteâ€element methods of numerical analysis in nonâ€linear aproach enable a reliable simulation of real reinforced concrete slabs behaviour under the conditions of complicated stressâ€strain state in all the stages of their behaviour under loading, including a stage of elasticityâ€plasticity state in concrete and reinforcement as well as formation and development of destruction mechanism. Numerical methods of modelling of critical behaviour of structures go beyond the borders of scientific research, being increasingly applied for solving nonâ€trivial engineering tasks when it becomes evident that possibilities of analytical approach, acceptable for the existing design codes are not sufficient. In such a case an exceptional attention is to be paid for verification of calculated models against experimental research of similar numeric models. This article reviews a case of complex experimentalâ€theoretical and numerical calculation and analysis methods applied for a reinforced concrete floor slab and column connection. The object of research is of exceptional interest as for practical calculation methods for this type of constructions following design norms of different countries revision and additional processing are necessary. The results of the reinforced concrete floor slab and column junction computer model nonâ€linear numerical analysis are presented and compared with the results of an experimental study. First Published Online: 14 Oct 2010

Refined non-linear static or dynamic analyses of reinforced concrete structures require the knowledge of the actual force-displacement or bending moment-rotation curves of each structural member, which depend on the crack widths and on the crack pattern, and after all on the slip between concrete and reinforcing steel. For this reason the definition of improved local models taking into account all these local aspects is a fundamental prerequisite for advanced assessment of r.c. structures. A numerical procedure which allows to predict the relative displacement between steel reinforcement and the surrounding concrete in a reinforced concrete element, once assigned the stress in the naked steel bar and the bond-slip law is discussed. The method provides as final outcomes the sequence of crack openings and the individual crack widths, regardless of the particular bond-slip correlation adopted. The proposed procedure is implemented referring to two relevant experimental case studies, demonstrating that it is able to predict satisfactorily actual strain fields and slips along the investigated reinforced concrete elements.

In the paper some case studies of damaged towers in Italy are presented: the Tower Masserano of Palace Ferrero - La Marmora at Biella, the bell tower of the Collegiata of San Vittore at Arcisate, and three medieval towers in Alba. A methodology is put forward for combining laboratory and nondestructive testing methods with monitoring systems in order to reach the goal of evaluating the state of conservation of historic towers and its evolution in time.

An experimental study was conducted to investigate the effect of web opening dimension on the behavior of reinforced concrete hybrid deep T-beam subjected to pure torsion. Four reinforced concrete hybrid deep T-beams were tested under pure torsion, where the three beams with different dimension of circular web opening and the other beam without opening as a reference beam. The testing program and experimental results are presented. The results show that dimension of circular web opening with diameter more than 100 mm significantly reduces the cracking and ultimate torque. It is also shown that the angle of crack inclination with respect to the longitudinal axis of the beam increases with the increase of web opening dimension. Abstrak . Suatu studi eksperimental telah dilakukan untuk meneliti pengaruh dimensi bukaan pada perilaku balok tinggi-T hybrid beton bertulang yang dikenai torsi murni. Empat balok diuji dibawah beban torsi murni, dimana tiga balok mempunyai dimensi bukaan yang berbeda dan satu balok tanpa bukaan sebagai tolok ukur. Program pengujian dan hasil-hasilnya disajikan dalam makalah ini. Hasil pengujian memperlihatkan bahwa dimensi bukaan dengan diameter lebih dari 100 mm secara signifikan mengurangi kekuatan torsi pada saat retak dan saat maksimum. Hasil eksperimental juga menunjukkan bahwa sudut kemiringan retak terhadap sumbu memanjang balok meningkat dengan meningkatnya dimensi bukaan.