Precast Concrete Shear Wall Structure Research Articles

Cyclic shear loading test for grout-sleeve joints in precast concrete shear wall structure

The reinforcement sleeve splicing technique has been utilized extensively in precast concrete shear wall structures, as it allows for achieving similar lateral capacity and deformation ability with cast-in-place (CIP) walls. However, investigation on shear behavior of the horizontal joint using this vertical connection is limited. In this study, six specimens of grout-sleeve (GS) joints designed for precast shear wall structures with single-row distributed reinforcements were subjected to cyclic loading tests under pure shear conditions, accompanied by three companion concrete-to-concrete (CC) joint specimens. The study investigated the influence of interfacial reinforcement ratio and surface roughness on the seismic performance of GS joints with different design details, aiming to understand their shear failure mechanism. The joint behavior under cyclic shear loading, including transverse dilation, strain development, and energy dissipation, was analyzed. Experimental results indicated that all specimens exhibited a significant pinching effect and strength degradation in hysteretic curves. Two types of shear failure, sliding failure along the grout-concrete interface with minimal wall cracking and diagonal compression failure with extensive concrete crushing above the grouted layer, are observed due to the roughness of the grout-concrete interface. This roughness also affects the curvature profile of interfacial reinforcement. A larger interfacial reinforcement ratio or a roughened interface can significantly increase the shear strength of the horizontal joints. However, although the GS joint and CC joint have similar failure modes, the variation in cracking patterns resulted in a reduction of up to 10.6 % in shear strength for the grout-sleeve joint. Nonetheless, it exhibited relatively ductile shear behavior compared to the concrete-to-concrete joint. A comparison of shear strength evaluation between five existing codes shows that Eurocode 2 gives the closest result to the test values.

Experimental Investigation of Seismic Performance of Precast Concrete Wall-Beam-Slab Joints with Overlapping U-Bar Loop Connections.

In the era of energy conservation and environmental protection, as well as the industrialization of buildings, precast concrete (PC) structures have been developed and increasingly applied in construction industries due to their advantages of outstanding workability and ecofriendliness. In order to verify the reliability of overlapping U-bar loop connections and a modified form of these connections, and study the seismic performance of PC wall-beam-slab joints with these connection methods, three full-scale wall-beam-slab joints were designed and tested under low reversed cyclic loading, including one cast-in-place (CIP) specimen and two PC specimens. Based on the test results, the seismic performance of the PC joints was studied by comparing their damage process, hysteretic loops and skeleton curves, load-carrying capacity, ductility, equivalent stiffness, and energy dissipation with those of the CIP joint. After analyzing the experimental results, the following conclusions can be drawn: the overlapping U-bar loop connection and its modified form are effective and reasonable; the specimen with the modified connection form showed slightly better mechanical properties; the failure mode of the PC joints was consistent with that of the CIP joint; and the generation, distribution, and development of cracks in the PC specimens were similar to those in the CIP specimen. In addition, the stiffness of the PC joints was similar to that of the CIP joint, and the load-carrying capacity, ductility, and energy dissipation of the PC joints were better than those of the CIP joint. Moreover, the research in this paper can also provide some guidance for assembling wall-beam-slab joints in PC shear wall structures.

Experimental investigation on seismic behaviors of precast concrete shear walls with sleeve grouting defects

The grouted sleeve connector is one of the most widely used connections in precast concrete shear wall structures. Due to the technology limit of the assembly workers, the sleeve grouting often has defects, which could significantly weaken their practical performance. Only considering the effect of defects on the bearing capacity of the sleeve connector cannot simulate the effect of defects in actual engineering. To this end, an experiment was carried out to investigate the seismic performance of precast concrete shear walls with sleeve grouting defects. Four full-scale precast concrete shear walls with different defect levels of insufficient grouting were designed and tested under cyclic loads. The development of concrete cracking, failure mode, hysteresis features, load-bearing capacity, stiffness degradation, structural ductility and energy-dissipation capacity are analyzed to reveal the influence of the sleeve grouting defects on precast concrete shear walls. The test results indicated that with the increase of the defect level, the opening gap between the bottom of the wall and the top of the foundation beam widened, and the failure mode changed from tensile fracture of reinforcing steel bar to anchorage failure of the tensile reinforcement on the defective side. Meanwhile, as the level of grouting defects increased, the bearing capacity decreased, and the specimen failed prematurely. The effect of the grouting defects on cracking load was minor, while they had a significant influence on the yield bearing capacity, peak bearing capacity and ultimate bearing capacity. The experimental results also indicated that the grouting defects caused the weakening of the stiffness, ductility and energy dissipation of the precast concrete shear walls. The presented work could be used for defect prevention and evaluation of precast concrete shear walls with sleeve grouting defects.

Experimental validation on seismic performance of a monolithic precast RC shear wall structure with novel connections

A novel monolithic precast concrete shear wall structure system was proposed, with four connector types: “cast-in-site elbow reinforced concrete joints,” “dry connectors,” “shaped steel shear keys,” and “shaped steel boundary elements” based on welding process with stable and high quality. The first two connect walls horizontally and the other two connect walls between adjacent stories. A high precast ratio, over 60%, can be achieved. To evaluate the strength, stiffness, ductility, and energy dissipation capacity of the proposed system, a full-scale three-story model was tested quasi-statically in the two horizontal directions. The model showed strong spatial response, demonstrating sufficient strength and stiffness to resist severe earthquakes. The coupling beams suffered shear failure damage. The connectors sustained large internal forces, surviving under simulated severe earthquake conditions. The external thermal insulation layers remained firmly attached to the precast wall panels, satisfying the design objectives.

Seismic performance of a new type of precast shear walls with non-connected vertical distributed reinforcement

To eliminate the shortcomings in the grouting sleeve and other connection forms in precast concrete shear wall structure induced by the poor grouting, difficult quality assurance, low construction efficiency, and high cost, a new type of monolithic assembled concrete shear wall structure with non-connected vertical distributed reinforcement was proposed in this paper. The new shear wall structure is composed of middle precast wall panels and cast-in-place boundary members. The vertical distributed reinforcement in the middle precast wall panels is not connected between the upper and lower floors. This technique was based on the normal section bearing capacity of equal strength and inclined section bearing capacity of equal strength compared with the cast-in-place shear wall structure. Three full-scale models of precast shear walls and one cast-in-place contrast specimen were tested for their seismic performance under pseudo-static loading. All precast specimens are cast based on the manufacture specification of the factory. By analysis of test results, including the failure modes, load-lateral drift hysteresis curves, bearing capacity, hysteretic characteristics, deformation components, ductility, rigidity degeneration, energy dissipation, and strain distribution, all the specimens were obtained and compared. Comparisons between test results indicate that the proposed shear walls have a similar bearing capacity as that of the cast-in-place shear wall and improved energy dissipation and ductility. Moreover, the specimen with inclined reinforcement performs better in drift capacity compared to companion specimens. The contribution of flexural deformation to the total displacement of each specimen is the largest, follow by the contribution of shear deformation, and the contribution of slip is the smallest. The strain of non-connected vertical distributed reinforcement of the precast panel did not yield during the loading process. The cross-section of the precast shear wall panel conforms to the assumption of plane cross-section according to the strain distribution before the reinforcement yields.

Experiment and numerical study of a new bolted steel plate horizontal joints for precast concrete shear wall structures

In a non-emulative precast shear wall structures, joints are the key to influence the overall mechanical performance under seismic actions. While wet joints are widely used in the precast reinforced concrete shear wall structure, they present problems such as collision of steel bars, inconsistency of the post-casting area and importantly, they cannot achieve the best potential of precast concrete structures. Hence, this paper proposes a new dry joint, which is a bolted C-shaped steel plate for the horizontal joint of precast shear walls. Four identical sub-assembly precast shear wall panels bolted with four distinct configurations of steel plates (plain, X-stiffeners, horizontal slots and vertical slots) were tested under reversed cyclic loading. It was discovered that the bolted steel plate with horizontal slots could improve the ductility and energy dissipation of the joint. Numerical models were calibrated by benchmarking with the experimental results. Through a systematic parametric study on the number and spacing of slots, thickness of steel plates and number of bolts, the results indicated that the number of bolts is the critical parameter that will affect initial stiffness, peak strength capacity and ductility of the proposed joint.

Experimental and Numerical Studies on the Seismic Performance of Precast Concrete Shear Wall Structures with an Energy Dissipation Cladding Panel

ABSTRACT A novel integrated precast concrete (PC) structural system, which maximizes instead of minimizing the interaction between the PC sandwich cladding panel and main structure, is proposed through the introduction of U-shaped dampers. To systematically validate the feasibility and reliability of this system, a full-scale PC wall-frame substructure equipped with an energy dissipation PC sandwich cladding panel, as well as two dampers, were tested under the pseudo-static load. A refined simulation method is proposed and validated. The damage evolution mode, energy dissipation capacity, and failure mode of such a structure are identified, providing a foundation for further investigation of such structures.

Effects of diaphragm flexibility on the seismic design acceleration of precast concrete diaphragms

A new seismic design methodology for precast concrete diaphragms has been developed and incorporated into the current American seismic design code. This design methodology recognizes that diaphragm inertial forces during earthquakes are highly influenced by higher dynamic vibration modes and incorporates the higher mode effect into the diaphragm seismic design acceleration determination using a first mode reduced method, which applies the response modification coefficient only to the first mode response but keeps the higher mode response unreduced. However the first mode reduced method does not consider effects of diaphragm flexibility, which plays an important role on the diaphragm seismic response especially for the precast concrete diaphragm. Therefore this paper investigated the effect of diaphragm flexibility on the diaphragm seismic design acceleration for precast concrete shear wall structures through parametric studies. Several design parameters were considered including number of stories, diaphragm geometries and stiffness. It was found that the diaphragm flexibility can change the structural dynamic properties and amplify the diaphragm acceleration during earthquakes. Design equations for mode contribution factors considering the diaphragm flexibility were first established through modal analyses to modify the first mode reduced method in the current code. The modified first mode reduced method has then been verified through nonlinear time history analyses.

Experimental and numerical investigation on the influence of PC window beam on the seismic performance of PC shear wall structures

Precast concrete (PC) window beams are usually prefabricated with PC shear walls and may affect the seismic performance of PC shear wall structures. To investigate the influence, two PC shear walls with different PC window beam depths were tested, and a refined FE numerical simulation method was proposed and validated. The experimental and numerical results indicate that double beam mechanism dominates the seismic performance of such specimens. The PC window beams can significantly improve the stiffness, load-bearing and energy dissipation capacities. To further investigate the influence at the structural level, seismic performance of a PC shear wall structure was evaluated. The analysis results indicated that the window beams can effectively reduce the inter-story drift ratio through the increase of stiffness and energy dissipation capacity of the structure, thus preventing the shear walls as well as beams from severe damage, and improve the seismic performance of structures. Such improvement of the seismic performance of PC shear wall structures becomes more obvious with the increase of the depth of PC window beams, which is consistent with the test results. The research outcome offers valuable experimental data, simulation method and useful reference for further investigation on seismic design of such shear wall structures.

Seismic performance of the spatial model of precast concrete shear wall structure using grouted lap splice connection and cast‐in‐situ concrete

Precast concrete structure has been increasingly used all over the world. Its seismic performance has always been the key factor of its application in earthquake‐affected zones, especially in China. A new precast concrete shear wall structure using grouted lap splice connection and cast‐in‐place concrete was proposed in this paper. Low‐cyclic reversed load testing was conducted on a one‐half scale spatial specimen of the bottom four stories of the new precast concrete shear wall structure. The test results were compared with the push‐over analysis results to evaluate the seismic performance of the specimen. The specimen showed good integrity and satisfies the current demands for Chinese seismic fortification. Moreover, due to the effect of infill walls strengthening the shear walls, and the effect of local cast‐in‐situ concrete regions constraining the precast components and connecting transverse walls to longitudinal walls, the specimen performed as tube structure and possessed excessive strength and stiffness.

Global Experimental Response of a Three-Story, Full-Scale Precast Concrete Shear Wall Structure with Reinforcing Bars Spliced by Grouted Couplers

Global Experimental Response of a Three-Story, Full-Scale Precast Concrete Shear Wall Structure with Reinforcing Bars Spliced by Grouted Couplers

Seismic performance of precast concrete shear wall structure with improved assembly horizontal wall connections

This study focuses on the seismic performance of precast concrete shear wall (PCSW) structures with improved assembly horizontal wall (AHW) connections. An improved AHW connection in a PCSW structure is first designed; its design approach, working mechanism, and construction method are described in detail. Then, two 1/4-scaled structure models—a PCSW structure model and a cast-in situ concrete shear wall (CCSW) structure model—are designed and constructed. The dynamic properties and seismic responses of the two structure models are compared via shaking table tests. The test results reveal that under earthquakes, the PCSW structure and the CCSW structure have similar failure processes, failure shapes, absolute acceleration responses, inter-storey drift responses, shear force responses, and shear-weight ratio responses; the improved AHW connections in the PCSW structure are useful and effective and can consequently meet the seismic requirements for wall. Finally, seismic responses of the PCSW structure are numerically simulated using the OpenSees software. The calculation results show that the seismic responses of the PCSW structure can be simulated using the OpenSees software under the assumptions that the mechanical performance of the AHW connection is akin to that of the equivalent cast-in-place connection and the longitudinal rebars in the AHW connection region are continuous.

Research Status on Reinforcement Connection Form of Precast Concrete Shear Wall Structure

With the rapid development of Chinese economy and the speeding up the process of urbanization, housing industrialization has been paid more and more attention. And the fabricated structure has been widely used in China. The key of precast concrete shear wall structure is the connection of precast components. The reinforcement connection can directly affect the entirety performance and seismic behavior of the structure. Different reinforcement connections have a great impact on the overall behavior of the structure. By studying the characteristics of the reinforcement connection forms used in the vertical connection and horizontal connection of precast concrete shear wall, it can provide reference for the research and development of the reinforcement connection forms in the future.

Seismic Performance of Base‐Isolated Precast Concrete Shear Wall Structure with AHW Connections

To improve the seismic performance and seismic reliability of precast concrete shear wall (PCSW) structure with improved assembly horizontal wall connections (AHW connections), base isolation technology was proposed to be applied in the PCSW structure. Two 1/4‐scaled structure models using the improved AHW connections were constructed: a lead‐rubber bearing (LRB) base‐isolated PCSW structure model and a base‐fixed PCSW structure model. Shaking table tests were conducted on these two models with three strong ground motions to assess the seismic performance of the structures. It was found that the improved AHW connections in the base‐isolated PCSW structure are useful and effective and that they fulfil the requirements to be met by the connections to withstand an earthquake. In addition, the maximum absolute acceleration and base shear force of the base‐isolated PCSW structure model were less than those of the base‐fixed PCSW structure model, and the isolation effect on the absolute acceleration responses and base shear responses increased with increase in the intensity of ground motions. In a word, the seismic performance and seismic reliability of PCSW structures can be effectively improved using base isolation technology. After this investigation, the seismic responses of the base‐isolated PCSW structure model were numerically simulated using OpenSees software. There was a reasonable agreement between the numerically simulated results and test results; thus, the numerical simulation method and analysis model used for the base‐isolated PCSW structure model were verified.

An innovative joint connecting beam for precast concrete shear wall structures

AbstractThe precast shear wall structure has outstanding features for green buildings due to its construction convenience, safety, high quality and low pollution. In general, precast concrete shear walls are connected by multiple joints. The joint between precast walls has very strong influence on the whole structure, which calls for more detailed investigation. A new kind of connection – the joint connecting beam – was developed to connect the vertical reinforcement in precast concrete shear wall structures. This innovative connecting method has the advantages of convenient operation and saving steel. To evaluate the performance and for better application of the joint connecting beam, an experiment on seven full‐scale specimens was conducted under cyclic loading, including two cast‐in‐situ walls and five precast walls with varying reinforcement and sectional heights of the joint connecting beam. A comparison was performed between cast‐in‐situ walls and precast walls with joint connecting beam, focusing on failure mode, hysteretic curve, skeleton curve, bearing capacity, ductility and energy‐dissipating capacity. The results show that the joint connecting beam can effectively transfer the load of precast walls, especially for squat precast walls. Moreover, finite element models were developed to simulate the performance of the specimens. The simulation results agree well with experimental results.

Research on the Design Method of a Scale Model of ECC Reinforced Concrete Precast Shear Wall Structure

Engineered cementitious composite (ECC) is a class of high performance cementitious composites with pseudo strain hardening behavior and excellent crack control. Substitution of concrete with ECC can avoid the cracking and durability problems associated with brittleness of concrete. In this paper, it is aimed to design a scale model of ECC reinforced concrete precast shear wall structure. Referencing the prototype structure which is a precast concrete shear wall structure in Nantong, Jiangsu Province, China, the size similarity constant is taken as 1/2. Consulting the scale similarity conditions, the similarity similar constants representing material characteristics, geometrical features, and load characteristics are calculated using the strength similarity theory. Besides, the reinforcements in the model structure are calculated and analyzed. The diameters of reinforcing steel bars in the model structure are determined by the principle of similar size. Equivalent principle of yield bearing capacity are used when there is no corresponding reinforcement selection. The research results of this paper will provide valuable preferences for design and analysis of ECC reinforced concrete precast shear wall structure.

RESEARCH ON SEISMIC PERFORMANCE OF A SPATIAL MODEL OF A NEW PRECAST CONCRETE SHEAR WALL STRUCTURE

Low-cyclic reversed load testing was carried out on a 1/2-scale four-story spatial model of the bottom of a new precast concrete shear wall structure. The test results are compared with the push-over analysis results of the prototype model to determine the seismic performance of the specimen. The new precast concrete shear wall structure, which meets the requirements of the current Chinese seismic fortification code and possesses excessive bearing capacity due to the effects of non-structural walls and effective confinement of local cast-in-situ regions, can be safely applied to practical engineering. As concrete infill walls prefabricated together with precast shear wall panels were used, it is necessary to pay sufficient attention to the effects of non-structural walls on the strength and stiffness of the main structure when designing according to current Chinese standards. Furthermore, the strength and stiffness of new precast concrete shear wall structure have been enhanced within the elastic phase, which has made its performance in the elastic-plastic phase complicated. Therefore, it is strongly recommended to perform detailed seismic effect analysis on a refined elastic-plastic model for this precast concrete shear wall structure.

Application of Precast Concrete Shear Wall Structure in Residential Projects

In order to adapt to the development of housing industrialization and the construction of energy-saving emission reduction requirements, research and application of precast concrete shear wall structure is becoming the hotspot in structural engineering. The DiJie international city B Neighborhood Project No. 8 residential building the form of engineering structure for precast shear wall structure. According to the practical application of prefabricated wall panels, balcony board, air conditioning board and stairs in residential projects, Introduced the key technology of component production, installation, cast structure node connection construction process using prefabricated in shear wall structure. In order to provide the reference for precast concrete shear wall high-rise residential design in the future.

傾斜地における壁式プレキャスト鉄筋コンクリート造住宅の施工

横浜市旭区白根町において, 現在, 斜面住宅を建設中である。敷地面積は約3.6ha, 敷地内の傾斜は平均18°である。特徴として, (1) 延床面積約23600m2, 戸数243戸, 棟数17と, 斜面住宅としては規模が大であること, (2) 基礎部分を除き, すべてプレキャスト化していること, (3) 部分的に地盤改良を併用していること, (4) 提案設計方式による設計施工であること, 等があげられる。本稿は, これらの特徴をもつ白根団地 (仮称) の設計概要と施工について述べるものである。