Seismic Resistance Performance Research Articles

A study of the seismic resistance performance of strengthened masonry walls using polypropylene mesh-composite on the surface

To investigate the seismic performance of masonry walls in village buildings strengthened with polypropylene mesh materials on the surface, five reduced-scale masonry walls were designed for low-cyclic reversed loading tests. The research observed the failure processes and characteristic forms of masonry walls, conducting a comparative analysis of the hysteresis curves and energy dissipation of the walls. Then, ABAQUS finite element software was used to simulate the performance of the strengthened walls to analyze the damage mode of these walls. The results indicated that under compression-shear loading, unreinforced masonry walls experienced shear failure along horizontal mortar joints, exhibiting lower shear load, lateral stiffness, and ductility. The reinforced walls with polypropylene mesh-composite effectively delayed and mitigated the failure. Weak zones in the wall gradually extended from the structural sides towards the central core area. Ultimately, after the reinforcement material had fully engaged, delamination failure occurred, leading to the formation of "X" or "Y" shaped through cracks. After reinforcement with single-side polypropylene materials, the load-bearing capacity of the wall increased by 165 % compared to the unreinforced wall. The ductility is improved compared to the unreinforced wall, whereas the initial stiffness increased by 133 %. Upon reinforcement with double-sided materials, the wall's load-bearing capacity surged by 180 %. The initial stiffness climbed to 171.3 %. The finite element analysis results closely aligned with the experimental data, suggesting that reinforcing the surface with polypropylene mesh-composite cement mortar significantly bolstered the wall's shear strength and deformation capabilities. This method effectively strengthens the seismic resistance of masonry structures.

Seismic performance of soft rock tunnel under composite support conditions

In order to effectively improve the seismic and impact resistance performance of soft rock tunnels, a composite support method was proposed and validated in the paper. The UDEC (Universal Distinct Element Code) model of soft rock layers was established, and the movement and subsidence characteristics of the roof and floor of the rock layers under impact loads was simulated and calculated. As a result, a composite support scheme with good cushioning performance was proposed. The top and sides of the tunnel were supported by a combination of anchor rods of different lengths and metal mesh, reinforced by steel beams and vibration absorbing filler around. The anchor rod was designed as a segmented loading structure, and can be set to different preloading forces based on the internal deformation of the rock layer. The dynamic response testing scheme was designed, and the results indicate that the segmented loading anchor rod has a significant buffering effect on the response to impact load, and can provide reasonable tension feedback at different stages. Research has found that when the water cement ratio is 0.5-1.5, the curing efficiency and strength are both higher. In order to compare the seismic performance of composite support and traditional constant resistance anchor rod support, local blasting experiments were conducted. Based on a blasting vibration tester, a data detection and transmission system were designed to obtain the vibration speed of the tunnel roof during the vibration process. The research results show that composite support can reduce the maximum vibration by more than 40 %, stabilize the fragmentation coefficient at 1.38, and have a very significant vibration reduction effect.

Dynamic centrifuge tests on the synergistic mechanism of pile-anchor structure retaining rock slopes

Pile-anchor reinforced slopes show to have better seismic resistance performance than other traditional supporting structures. However, their bearing mechanisms are not yet fully understood. In this study, dynamic centrifuge model tests are carried out to study the dynamic response and synergistic mechanism of rock slope reinforced by pile-anchor composite structures under seismic loading. The centrifuge model is devised by following the scaling principle, and the properties of the model materials are determined by laboratory tests. Some parameter studies are carried out considering the anchor elastic modulus, pile bending stiffness, and pile embedding depth. The test results are discussed in terms of the failure mechanism of the slope to help better understand the synergistic mechanism of the pile-anchor structure in seismically active areas.

Optimization of the Granular Mixture of Natural Rammed Earth Using Compressible Packing Model

Rammed earth (RE) construction is an ancestral technique that allows for the building of durable and resistant constructions. RE buildings are sustainable and environment-friendly, and ensure energy optimization during the construction cycle. For these reasons, many of the following RE characteristics are studied: mechanical strength, seismic resistance, and thermal performance. However, the mix design of RE soils has been rarely studied. There is practically no scientific approach that allows for defining precise dosages of clay, silt, sand, and gravel used in RE materials. The broader aim of this article is to determine a scientific mix design method to find an optimal RE granular mixture. The compressible packing model (CPM) is applied to study the effect of every granular class on compactness and define the optimum mixture. Many tests have been conducted such as the Modified Proctor, compression test, and ultrasonic velocity pulse test to evaluate the relevance of this model. The results suggest many granular corrections for RE material that considerably enhance compactness and unconfined compressive strength (UCS). It was found that one granular correction provides a 137% increase in the initial UCS. Therefore, this approach enables the defining of which granular class is to be added or reduced to optimize the mechanical properties of RE.

AN EXPERIMENTAL STUDY ON HORIZONTAL RESISTANT MECHANISM OF SANDWICHED PANEL STRUCTURE OF INSERTED METHOD

Recently, in Japan, there are some discussions to promote the use of timber resource in the field of architectural buildings. For examples, some latest mid-rise buildings are constructed using wooden material, such as the facilities of Tokyo Olympic 2020. We can experiment the dairy life and architectural space with timber materials, which often has attracted attention. In Japan, the demand of low-rise prefabricated steel building is recently increasing. However, to satisfy the seismic resistant performance of building, they are required to have lots of seismic resistant wall which restrict layout of wall and opening. The object of this study is to develop low-rise prefabricated steel building with high seismic resistance performance using hybrid structural system using wooden materials. We suggest the method of sandwich panel structures, which steel column is sandwiched by structural plywood connected by bolt joints. To improve productivity and seismic resistance, this paper suggests the construction process using inserted wall sliding construction method. To clarify the resistant mechanism and structural performance, a horizontal loading test is conducted. From the results, the resistant mechanism in the diagonal direction is appeared; it means that the effective resistant system can be obtained. Also, the composite effect of steel and plywood is presented to give the high strength and rigidity. From the observation of test results, the analysis model is assumed. And also, it is confirmed that the proposed model can evaluate the strength of test results.

Experimental study on seismic performance of resilient recycled aggregate concrete shear walls

A type of recycled aggregate concrete shear wall was proposed in this work, which used the painted ultra-high-strength steel (UHSS) reinforcements with low bond strength and high yield strength in the boundary elements. For investigating the seismic resistance and resilient performance of this shear wall, six shear walls with the shear-to-span ratio of 1.5 were fabricated and tested under the cyclic loads. The variables studied in this paper were the types of the longitudinal reinforcement in the boundary elements, the existence of steel fibers, the presence of the concealed bracings (X-shaped) and the different axial compression ratios. The test results indicated that specimens with the UHSS reinforcement in the boundary elements decreased the residual deformation substantially and improved the resilient properties. The higher axial compression ratio enhanced lateral force resistance of shear wall but aggravated concrete damage which was adverse to the resilience. In addition, the utilization of steel fibers in concrete significantly reduced the crack width. The shear wall including concealed bracing not only showed much higher lateral force resistance, but also had desirable resilient performance under the large deformation. Finally, a simplified calculation model for such shear walls was proposed on the basis of experiment. And the good accuracy of the calculation model was verified by comparing the calculation results and the measured results.

Seismic collapse behavior of steel structures with a smart axial polyurethane friction damper

Shape memory alloys (SMA) are utilized in various engineering fields, owing to their unique properties. In this study, the collapse behavior of steel structures designed with a self-centering damper under seismic sequences was investigated. The proposed damper was made of SMA plates, friction devices, and polyurethane springs called axial polyurethane friction (APF) -SMA dampers to provide desirable damping capabilities and good self-centering behavior. Concentrically braced 14-story steel frames using four types of bracing systems (split X, chevron V, inverted chevron IV, and diagonal) were modeled in OpenSees with and without the APF-SMA damper to evaluate their seismic resistance performance. An incremental dynamic analysis (IDA) was performed for the frames, and the maximum inter-story drift IDA curves of the frames were developed and compared. The analysis results indicated that the APF-SMA damper limited the maximum inter-story drifts of the conventional steel frames and effectively reduced the residual inter-story drifts of the braced frames. Finally, the advantages of the proposed APF-SMA over the conventional braced frames were demonstrated through probabilistic analyses of the results based on the nonlinear response history analyses.

Anti-Seismic Performance Evaluation of Waterproofing Materials for Underground Pile Wall Structures.

This study introduces and demonstrates the application of an experimental regime for anti-seismic performance evaluation of waterproofing materials used for concrete pile walls. Concrete pile walls are subject to high degrees of seismic load, and the resultant stress can affect the waterproofing integrity of the structure, but there is currently no existing methodology or standard for evaluating this property of waterproofing materials. To propose and conduct this evaluation, a new testing apparatus was designed and manufactured to test an installed waterproofing material’s seismic resistance performance. Under three different inclined angle conditions (0°, 10°, 20°), each with three different rotation speed conditions (10, 20 and 30 rotations per minute), three types of waterproofing materials were subjected to 30 s of increasing seismic stress and tested for their waterproofing performance. Waterproofing performance was determined by whether the specimen installed with the respective type of material was able to prevent leakage path formation during the seismic stress, and the performance was summarized and compared based on the average results for four specimens of each material type and the duration before leakage occurrence. Results of the demonstration testing yielded significantly different results for the tested material types, prompting the need to further investigate different types of waterproofing materials, products, and techniques for a comprehensive understanding of waterproofing material response properties against seismic stress. The demonstration process shown in this research was intended to serve as a proposal for the development of these performance evaluation criteria, methodologies, and equipment for possible future application.

Seismic collapse resistance performance on out-jacketing frames with concrete-encased CFST columns for adding storeys

This research paper conducted a hysteretic behavior simulation on a single-span and single-storey frame composed of prestressed concrete-encased steel beams and concrete-encased concrete filled steel tube (CFST) columns. The hysteretic parameters of stiffness degradation, strength degradation and pinching behavior for members were suggested according to tested results. After that, an analytical model for corresponding out-jacketing frames with single-span and multi-storey was developed, and amounts of elastoplastic seismic response analysis were conducted for seismic fortification intensities 7 and 8 with various site-classes and design earthquake groups under rare earthquake. The results indicated that, the out-jacketing frames assigned to Intensity 7 with Site-classes I0 to III behaved perfectly in seismic collapse resistance performance, which could be designed as regular frames by using China's current codes; while referring to Intensity 8, a certain amount of out-jacketing frames assigned to Site-classes I0 to III had inter-storey collapse mechanism, and several design proposals were developed to prevent collapse failure by measurements of enhancing seismic grade.

Axial compressive behaviour of double steel-concrete shear wall constrained with ribs and bars

The double steel-concrete shear wall combines the advantages of steel and concrete effectively, with high bearing capacity, good plasticity, superior seismic and fire resistance performance, saving materials and simple construction, and has obvious advantages in the application of high-rise buildings, especially super high-rise buildings. Research on axial compressive behavior of double steel-concrete shear wall constrained with ribs and bars is less. In this paper, the constitutive relation of double steel-concrete column with ribs and bars is used to change the relevant parameters and program to analyze the influence of ribs and bars on the axial compression performance of double steel-concrete shear wall.

Structural Performance Analysis of Cross Laminated Timber (CLT) Produced From Pine and Spruce Grown in Turkey

Wooden buildings with many advantages such as being lightness, durability, earthquake resistant, healthy, insulating, and esthetic are suitable for all kinds places especially earthquake zones. Cross-laminated timber (CLT) has increasingly become a viable alternative to other structural materials, mainly because of its excellent properties related to sustainability, energy efficiency, and speed of construction. This has resulted in the recent emergence of a significant number of CLT buildings constructed around the world. This is a study on determining the properties of CLT panels manufactured from wood species grown in Turkey and investigating of the structural behaviour and seismic resistant performance of them. Lumbers of 100 mm (width) x 50 mm (thickness) x 2400 mm (length) used in CLT manufacturing were obtained from eastern spruce (Picea orientalis L.) and scots pine (Pinus slyvestris) logs. Two replicate three-layered CLT panels of 2400 mm × 2400 mm × 150 mm in size were manufactured for each group. Density of the CLT panels was determined according to EN 323. The seismic resistant performance of the CLT shear walls was determined according to ASTM E 72 standard. CLT panels manufactured from scots pine gave higher seismic performance than those of CLT panels manufactured from spruce. The maximum load capacity of the walls increased with increasing the density values of the CLT panels.

Verification of seismic resistant performance of developed original cross-laminated timber core structure method by shaking table experiment

In recent years, development of wood engineering is gradually increasing. Instead of using many wood columns, cross laminated timber is expected for constructing spacious open space building. Since cross-laminated timber has high rigidity and strength, cross-laminated timber is expected to be used as earthquake resistant wall or floor diaphragm that makes the span of building can be increased and the position of the wall can be adjusted openly. In order to optimize the performance of cross-laminated timber for open space building, original cross laminated timber core structure method was developed. In this paper, the development concept of original cross laminated timber core structure method will be explained. In this method, the joint connection for each element such as joint connection for wall-concrete foundation, wall-beam, and wall to hanging wall was also developed. The experiment to verify the strength and rigidity of each connection has been conducted and the result will be described. The shaking table experiment of 3-story open space building constructed by original cross laminated timber structure using varies earthquake waves was conducted. In this experiment natural period, shear force for each floor, story drift, and building response data is taken. The result shows the structure designed by original CLT core structure method is satisfy the requirement based on Japan cross-laminated panel structure regulation.

Parametric Study of Superelastic-Sliding LRB System for Seismic Response Control of Continuous Bridges

Abstract To enhance the normal service adaptability and seismic resistance performance of isolation continuous bridges, a superelastic-sliding lead rubber bearing (SSLRB) isolation system was devel...

Seismic resistance of locking ball devices and optimal design for irregular continuous bridges with one fixed pier

In order to reduce seismic response of fixed piers in irregular continuous bridges and improve the overall seismic resistance performance of bridges, locking ball devices were installed between the sliding piers and girders of bridges. These devices allowed the sliding piers to share seismic load from the superstructure with the fixed pier, according to the potential seismic resistance capacity of sliding piers. A shake table test and a simulation of the finite element model of a three-span irregular continuous bridge were conducted. Then, taking a typical five-span irregular continuous bridge as an example, the seismic resistance mechanism and the influence of locking ball devices on the seismic responses of sliding piers were analyzed. Optimal designs of locking ball devices were studied to protect sliding piers. The results show that locking ball devices installed on sliding piers can effectively reduce the seismic response of the fixed pier, but they may increase the seismic response of the sliding piers installed with locking ball devices, and that of the irregular continuous bridge as a whole. Both the acceleration threshold and the lock gap of the locking ball device strongly influenced the seismic resistance effect. The main parameters of the locking ball devices should be optimized based on the structural characteristics of the bridge, so as to obtain a better seismic resistance effect. Adjusting connection stiffness of locking ball device can reduce the seismic response of the short sliding pier and can protect it, but changing the lock gap is not an effective way of protecting the short pier. It is necessary to optimize the arrangement of the locking ball devices.

Seismic Performance of a New Type Concrete-Filled Precast Concrete Tubular Column

To investigate the seismic behaviour of a new type of concrete-filled precast concrete tubular column, five concrete-filled precast concrete tubular columns varying in concrete strength and stirrup ratio were tested under cyclic loading. The behaviours of the failure mode, hysteretic curve, skeleton curve, bearing capacity, deformability, displacement ductility and energy dissipation were studied to evaluate the seismic resistance performance of the columns. The results show that the failure mode of the concrete-filled precast concrete tubular columns was flexural failure, and the hysteretic curve had a plump shuttle shape, which indicates that the concrete-filled precast concrete tubular column has good energy dissipating capacity. The bearing capacity of the specimen was increased with increasing concrete strength of the precast tube. The stirrup ratio has little effect on its bearing capacity, whereas it has a significant effect on the deformation, ductility and energy dissipation. The story drift of the specimens can meet the requirements of the elastic plastic story drift limit value of 1/50 of the code in China, and the ductility coefficient is greater than 3, which demonstrates that the concrete-filled precast concrete tubular column has excellent seismic properties.

Earthquake Protection View on Expanding Damage to Wooden Building in a Region Exposed by a Series of Cyclic Events: Simulation of Secondary Damage Caused by Aftershocks with Probabilistic Estimation of Degrading Seismic Resistant Performance

Earthquake Protection View on Expanding Damage to Wooden Building in a Region Exposed by a Series of Cyclic Events: Simulation of Secondary Damage Caused by Aftershocks with Probabilistic Estimation of Degrading Seismic Resistant Performance

Seismic resistance performance of a utility tunnel in saline soil foundation based on new cementitious composite materials

Abstract Because soluble salt in saline soil dissolves with water, utility tunnels built in saline soil foundation are more likely to damage due to by groundwater and earthquake. In this study, new cementitious composite materials were developed by using slag, building gypsum, quicklime, and magnesia. The unconfined compressive strengths of the saline soil solidified by new cementitious composite materials and cement are investigated, and the optimum proportion of the different components of the new cementitious composite materials is determined. We found from microscopic characteristics of the saline soil solidified by the new cementitious composite materials and cement that the new materials could better absorb chloride ions. Finally, the new cementitious composite materials were applied to saline soil foundation reinforcement of a utility tunnel. By using the finite element method (FEM) and shaking table tests, it can be seen that the displacement, acceleration and extent of damage of the utility tunnel after saline soil foundation reinforcement using new cementitious composite materials significantly decreased; therefore, the new cementitious composite materials can improve the seismic behaviour of the utility tunnel and shows potential future engineering application value.

Minimum wall-area index for low-rise concrete housing

Medium- and low-rise buildings with different construction systems have exhibited low seismic-resistant performance during recent earthquakes primarily because of low wall-area index. The increasing demand for low-income housing in Latin America, particularly in Colombia, has fostered the construction of buildings with reinforced concrete walls using industrialized construction systems. This study proposes two equations for calculating wall-area index for low-rise concrete housing in terms of the height of the house, soil-structure interaction, seismic hazard zone and allowable drift. Seismic-resistant structural analyses were performed on nine housing prototypes considering six study variables: modeling method, seismic hazard zone, support type of walls, concrete cracking, seismic analysis method, diaphragm type, mass distribution and energy dissipation coefficient. Results derived using the proposed equations are compared with wall-area index computed using equations proposed by building codes.

Experimental research on the time-varying law of performance for natural rubber laminated bearings subjected to seawater dry-wet cycles

Natural rubber laminated bearings (NRBs) in sea-crossing or offshore bridges are extremely vulnerable to seawater dry-wet cycles due to weather conditions, wind, waves, and other factors in coastal areas. Seawater dry-wet cycles test was conducted on 20 NRBs and 63 rubber sheets for 60 days to investigate the influence of seawater dry-wet cycles on basic NRB performance. The change laws that govern the NRBs’ horizontal and vertical stiffness were obtained via seawater dry-wet cycles test. In addition, the proposed constitutive parameters of the rubber material were used to establish a finite-element model of the NRBs to simulate and analyze the bearings’ performance and time-varying law. The test results were then compared with the fitted and simulated results. Finally, the performance deterioration law of the NRBs was predicted over a 120-year lifespan based on the extrapolation of the 60-day test results, and the finite element analysis of the performance for NRB within 120-year service life was done to verify the reliable of the prediction result. The 60 days test results show that the NRBs’ horizontal and vertical stiffness increased by 23% and 7%, respectively, after test for 60 days, and horizontal and vertical stiffness increased linearly as the seawater dry-wet cycles test time increased. The findings presented in this paper lay a foundation for further research on the performance of NRBs and will play an important role in the study of the seismic resistance and life-cycle performance of sea-crossing bridges and other structures subjected to seawater dry-wet cycles.

Seismic Resistance Performance of Shear Wall Structure of Assembled Coastal Buildings

ABSTRACT Xiang, Y.; Wei, Y.; Wang, Y., and Meng, K. 2018. Seismic resistance performance of shear wall structure of assembled coastal buildings. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 267–271. Coconut Creek (Florida), ISSN 0749-0208. The seismic resistance bearing and deformation capacity of the traditional wall structure is poor, and the force is not uniform, which leads to the high risk of building collapse. In order to solve this problem, the seismic resistance performance of the shear wall structure of the assembled coastal buildings is analyzed in this paper. On the basis of monotonic load, the mechanical properties of the structure under cyclic loading are analyzed, and a nonlinear numerical model is constructed. The fitting degree of the seismic resistance bearing capacity of the assembled shear wall structure is calculated. On the basis of this, the displacement ductility coefficient and the equiva...