RC Plates Research Articles

Bending behavior of segmental precast diaphragm walls using bolted sleeve joints

AbstractTo study the bending behavior of segmental precast diaphragm walls using bolted sleeve joints, 2 full size specimens were tested. Both BC and EC specimens were connected using bolts with steel sleeves as positioner. BC specimen was consisted of two fully RC plates while EC specimen had precast holes in the concrete walls for lightweight treatment. Ultimate strengths, deformations, strains and failure modes were obtained from the test results. Finite element models were developed using ABAQUS and verified against the test results. The verified finite element models were used to further analyze the stress state of specimens under different loading. It indicated that the bolted sleeve joint exhibited good bearing capacity and bending stiffness. The lightweight treatment in the concrete part had minor effect and the design requirement could be satisfied.

Analysis and Resemblance of Seismic Effect on High Rise Building with & without Shear Wall using STAAD Pro

In present age one of the most volatile natural disaster is earthquake, in which all procedure applied for earthquake resistant in multi storied structures any where shear walls are the most preferred process. In RC plates (shear wall) have properties of inelastic & stiffened member. It is a part of structure which is provided for resisting horizontal forces (like wind force, earthquake force, etc). It is very essential to determine capable, and ideal location of shear wall. In this paper we study of G+10 Storey building in Zone IV is conferred. In this article focuses on two different models with and without using shear walls in high rise building at different positions. This analysis is done by using STADD-pro Software by seismic analysis & wind effect.

Robust design procedure for RC plates and shell structures using developed advanced sandwich model

In recent years, a notable increase in the number of complex concrete roofs has been observed. Simultaneously, the design codes lack design approaches for such structures in which the elements are subjected to combined forces (membrane and transverse) and moments (flexure and torsion). The finite element-based design (FEBD) has been provided for these structural elements; however, it is not widely adopted for the design. Hence, there is an urgent need to fill this gap. Therefore, an automatic FEBD procedure is developed in this study based on the equilibrium consideration, named the developed advanced sandwich model (DASM). The element cracking inspection was performed according to the multi-axial compression state of concrete. Subsequently, the DASM was developed to account for the effect of transverse shear forces. The proposed design algorithm was developed using a Python script linked with ABAQUS software to perform an automatic design for all elements and to be presented as a practical design tool. Additionally, the damage-based analysis was performed as an assessment tool to demonstrate the efficiency of the proposed design procedure. This study illustrated that using the DASM reduced the steel reinforcement by up to 40% and increased the ductility by 10–15%. Also, it is observed that the ultimate capacity of the considered examples, including the solid plate and flat plate, slightly decreased by 4.1% and 1.8% (less than 5%), respectively, which hardly affects the overall response of the designed structure. Indeed, these results demonstrate the efficiency of the developed procedure. In summary, the results of this study indicate that the proposed design framework (DASM) presents a highly accurate, relatively simple, and robust procedure for designing plate and shell structures with complex geometry, where the design process can be completed on a standard personal computer in a few seconds.

Progressive damage in pretensioned and reinforced concrete plates against repeated impacts

This study is planned to explore the performance of pretensioned concrete (PC) plates under multiple impacts. A detailed investigation has been carried out on pretensioned concrete plates (0.8 × 0.8 m2) against drop impact. The plates prepared using Mix-40 and Mix-60 grade concrete have been induced with two different levels of initial prestress, that is, 1/10 and 1/5 (i.e. level-1 and level-2) times the strength of the concrete. The PC plates have been impacted by a falling impactor (2382 N) dropped from 0.5 m height. The response of those plates has been obtained and compared with the reference RC plates. The post-impact performance of the damaged plates has been further discovered by subsequently dropping the impactor multiple times from the identical height. The FE simulations of the problem have been carried out using Johnson-Holmquist-2 and metal-plasticity constitutive models for concrete and steel, respectively. The models have been initially verified with the experimental results available in literature, and subsequently the simulations for drop impact have been carried out. The simulation results are also compared with the results of drop impact experimentations performed. In general, both the pretensioned and reinforced concrete have witnessed flexural cracks at the beginning, such that pretensioned concrete witnessed lesser cracks compared to reinforced concrete. As the number of drops increased, one major splitting crack developed only in pretensioned concrete, whereas the reinforced concrete exhibited additional punching cracks. For a given concrete grade, the pretensioned concrete level-2 witnessed the smallest damage, minimal cracks, and also minimal spalling followed by the pretensioned concrete level-1 and reinforced concrete. The reinforced concrete absorbed the minimal impact energy followed by the pretensioned concrete level-1 and level-2 under the multiple impacts. The FE simulations predicted the impact force and reaction within 11.9 and 9.9% variation, respectively, with the corresponding experimental results.

An analytical model to predict the compressive damage of concrete plates under contact detonation

Explosions threaten the safety of buildings and occupants by inducing severe damage to concrete structural elements. The effects of close-in and contact loading situations on RC plates have been investigated in literature and the common approaches employ field test results condensed in engineering charts based on cube-root scaling. In this paper, a new analytical model based on a physical framework is developed to (a) investigate shock wave attenuation along the depth of the concrete plate and (b) predict the size of crater damage. The analytical model for shock wave pressure is discussed in comparison to prediction data from established numerical models and existing experimental results. Moreover, consistency of the newly proposed model with established scaling rules is verified with respect to crater size.

Experimental Behavior and Design of CFT-RC Short Columns Subjected to Concentric Axial Loading

AbstractConcrete-filled steel tube (CFT)–RC composite members consist of multiple CFT columns connected by RC plates or webs. CFT-RC composite members have been used in different types of structure...

BIM Standards for Automated BEM Structural Analysis and Design of RC Plates

AbstractThis paper introduces a new system that utilizes the advantages of boundary element analysis in structural engineering applications. A standardized building information model (BIM) for automated structural analysis and design of reinforced concrete plates based on the boundary element method (BEM) is proposed. Based on the model view definition approach, BIM standards are presented for the preprocessing and postprocessing of BEM analysis. Furthermore, standards are proposed for automated structural design of structural slab and beam elements based on the BEM analysis results. For each of the BIM components, standards are provided for the object structure, data flow, and graphical user interface (GUI). The extensibility of the software and applicability for a wide range of research and practical applications are considered in all the proposed standards. The system created can act as the basis for structural analysis and design of building floor and foundation problems. Object-oriented programming i...

Application of FRP Strap in an Innovative Prestressed Method

Fiber-reinforced polymer (FRP) strap is one of the FRP forms. Its width is small and its thickness is large. The wave-shaped-gear-grip anchorage (WSGG) was developed specifically for the FRP strap. A brand-new method has been developed for externally anchored FRP sheet prestress strengthening, which makes full use of the features of WSGG anchors by fixing both ends and then fastening the middle to force FRP sheets to elongate geometrically and generate a pretension. Worn bridge members (solid RC plates of 8 m long) removed from the Cheng-Yu Expressway were used in this experiment of externally anchored CFRP strap prestressed strengthening. The experiment results demonstrated that the proposed method for the application of prestressing FRP straps is very simple, easy, and technically practical, and can significantly enhance the effectiveness of strengthening. It was also shown that the proposed method will have broad applications.

1406 貫通を考慮したRC版の衝撃強度評価への解析モデル検討実験検証(OS14.衝撃・崩壊問題(2),オーガナイズドセッション)

1406 貫通を考慮したRC版の衝撃強度評価への解析モデル検討実験検証(OS14.衝撃・崩壊問題(2),オーガナイズドセッション)

Shell finite element analysis of RC plates supported on columns for punching shear and flexure

Purpose – The paper aims to present a method of implementing layered shell finite elements for punching shear analysis of reinforced concrete slabs. The emphasis is on the influence of different material modelling parameters on the calculated results.

Design and ultimate behavior of RC plates and shells

An iterative numerical computational algorithm is developed to design a plate or shell element subjected to membrane and flexural forces, which is based on equilibrium considerations for the limited ultimate state of the reinforcement and cracked concrete. Equations for capacities of top and bottom reinforcements in two orthogonal directions have been derived. To verify the design algorithm on the element level several experimental examples are designed. Nonlinear inelastic analyses are performed with the designed examples using the Mahmoud-Gupta’s computer program to show the adequacy of the design equations. The calculated ultimate strengths are from 3 to 18% higher than the ultimate strength obtained from the test results, except in one example. On the global structural level, a design is performed for a hyperbolic cooling tower to check the design strength to verify the adequacy of the design algorithm. Based on the ultimate nonlinear analysis performed with the designed reinforcement, the analytically calculated ultimate loads exceed the design ultimate load from 26 to 63% for analyses with various amounts of tension stiffening effect. Even though the ultimate loads are dependent on the tensile properties of concrete, the calculated ultimate loads are higher than the design ultimate loads for the cases considered. This shows the adequacy of the design algorithm developed, at least for the structures studied. The presented design algorithm for combined membrane and flexural forces can be evolved as a general design equation for reinforced concrete plates and shells through further studies involving the performance of many more designs and analyses of different plate or shell configurations.

Design and ultimate behavior of RC plates and shells: two case studies

Two cases of design are performed for the hyperbolic paraboloid saddle shell (Lin-Scordelis saddle shell) and the hyperbolic cooling tower (Grand Gulf cooling tower) to check the design strength against a consistent design load, therefore to verify the adequacy of the design algorithm. An iterative numerical computational algorithm is developed for combined membrane and flexural forces, which is based on equilibrium consideration for the limit state of reinforcement and cracked concrete. The design algorithm is implemented in a finite element analysis computer program developed by Mahmoud and Gupta. The amount of reinforcement is then determined at the center of each element by an elastic finite element analysis with the design ultimate load. Based on ultimate nonlinear analyses performed with designed saddle shell, the analytically calculated ultimate load exceeded the design ultimate load from 7% to 34% for analyses with various magnitude of tension stiffening. For the cooling tower problem the calculated ultimate load exceeded the design ultimate load from 26% to 63% with similar types of analyses. Since the effective tension stiffening would vary over the life of the shells due to environmental factors, a degree of uncertainty seems inevitable in calculating the actual failure load by means of numerical analysis. Even though the ultimate loads are strongly dependent on the tensile properties of concrete, the calculated ultimate loads are higher than the design ultimate loads for both design cases. For the cases designed, the design algorithm gives a lower bound on the design ultimate load with respect to the lower bound theorem. This shows the adequacy of the design algorithm developed, at least for the shells studied. The presented design algorithm for the combined membrane and flexural forces can be evolved as a general design method for reinforced concrete plates and shells through further studies involving the performance of multiple designs and the analyses of differing shell configurations.

Nonlinear Analysis of RC Shell Structures Using Laminated Element. I

An incremental variational formulation is presented for large deflection analysis of elastic‐plastic continuum by considering the energy consistency of a nonlinear multivariable discrete system based upon incompatible trial functions. The functional is given in orthogonal curvilinear coordinate system and the initial stress procedure has been introduced. Equilibrium imbalance correction is included to prevent drifting of the solution during the incremental process. As an initial application of the suggested formulation, a hybrid stress laminated shell element, in which an energy constraint is introduced to improve the element performance, has been developed to analyze the through‐thickness plastic behavior and the progressive cracking in RC plates and shells. It is of quadrilateral shape with only four corner nodes and can be used for both shallow and deep laminated shells with satisfactory numerical characteristics. Example problems are also included to illustrate the element performance.

State of Stress in RC Plates under Service Conditions

A theory regarding the stresses of reinforced concrete shear walls and slabs under service loads is presented. Stresses are determined before and after cracking. The reinforcement provides forces and moments that compose tensors. These tensors, together with the corresponding concrete tensors, constitute the reinforced concrete tensors. After cracking, the force and moment tensors of reinforcement appear in their complete form, i.e., not only with the axial forces but also with the shear forces of steel bars. The existence of these shear forces is proved theoretically, and their magnitude is determined by the compatibility conditions of the strains at the crack. Equating the tensor of the internal forces or moments of plate with the tensor of reinforced concrete forces or moments, respectively, we obtain the angle of cracks, the steel stresses and the forces or moments of concrete between the cracks. Derived equations are applied to plates reinforced with an orthogonal reinforcing net or with reinforcing bars in one direction. Experimental and theoretical results show a very good agreement.

Nonlinear Layered Analysis of RC Plates and Shells

A layered nonlinear finite element analysis including the elastoplastic behavior of steel, bilinear elastoplastic behavior of concrete, and limiting tension of concrete is presented. The incremental-variable elasticity analysis technique is used to obtain the load deflection curve for any general plate or shell. The need for a shear retention factor to provide the torsional and shear stiffness for cracked concrete is examined. The failure of the constitutive relations for a layered material to uncouple and the resulting importance of the inplane degrees-of-freedom is also considered. Finally, some numerical examples, both plates and shells, are presented to demonstrate the accuracy of the incremental analysis.