Pseudo-dynamic Tests Research Articles

A modified curve-approximated hysteretic model for partially concrete-filled steel tube bridge piers

A modified curve-approximated hysteretic model for partially concrete-filled steel tube (PCFST) bridge piers is developed based on the previous research work. The proposed model, which consists of a series of quadratic and cubic curves and takes into account the P-Δ effect, pinching behavior in unloading-reloading hysteretic loops, and deterioration of strength and stiffness, can be used to precisely describe complicated hysteretic behavior of cantilever-type PCFST bridge piers. Parameters of this model are calibrated on the basis of quasi-static cyclic test results. To verify the validity of the proposed model, a total of 12 pseudo-dynamic tests were carried out. The detailed comparisons of different seismic performance indices between experimental and numerical results, such as the maximum response displacement, the residual displacement, and the amount of energy dissipation, indicated that the proposed model can be an acceptable complementary and assisting tool for the nonlinear seismic response assessment of PCFST piers.

Nonlinear dynamic response of R/C buildings strengthened with novel stud-typed seismic control system using non-buckling slit damper

This study proposed a new stud-type seismic control system using a Non-buckling Slit Damper (NBSD), which overcomes weaknesses of existing seismic control systems and can be effectively applied to reinforced concrete (R/C) buildings, and performed a material test to evaluate the material performance and energy dissipation capacity of NBSD. A pseudo-dynamic test was performed on a full-size two-story frame specimen based on non-seismic detailed R/C buildings, thereby demonstrating the seismic strengthening effect or, specifically, the restoring force, energy dissipation capacity, and seismic response control of the proposed stud-type seismic control system when applied to existing R/C frames. The results of the material test and pseudo-dynamic test were utilized to propose restoring force properties for nonlinear dynamic analysis of the frame specimen. Nonlinear dynamic analysis was carried out based on the proposed restoring force properties, and results were analyzed against the results of the pseudo-dynamic test. For the purpose of commercialization, nonlinear dynamic analysis was performed on non-seismic detailed R/C buildings strengthened with the proposed NBSD stud-type seismic control system; the seismic strengthening effect was verified through a before-and-after comparison of seismic response load, displacement, energy dissipation capacity, damper load, and displacement response. During an earthquake with a peak ground acceleration of 200 cm/s2, non-seismic R/C frames were expected to undergo shear failure, while frames strengthened using the NBSD stud-type seismic control system would have light damage. Even when the most severe earthquake possible in Korea was assumed (300 cm/s2), the NBSD stud-type seismic control system was found to be effective in minimizing damage.

Seismic Strengthening Effects of Full-Size Reinforced Concrete Frame Retrofitted with Novel Concrete-Filled Tube Modular Frame by Pseudo-Dynamic Testing

The present study proposes a new seismic retrofitting method using a concrete-filled tube modular frame (CFT-MF) system, a novel technique to overcome and improve the limitations of existing seismic strengthening methods. This CFT-MF seismic retrofitting method makes the most of the advantages of both concrete and steel pipes, thereby significantly improving constructability and increasing integration between the existing structure and the reinforcement joints. This method falls into the category of typical seismic retrofitting methods that focus on increasing strength, in which the required amount of seismic reinforcement can be easily estimated. Therefore, the method provides an easy solution to improving the strength of existing reinforced concrete (RC) structures with non-seismic details that are prone to shear failure. In the present study, a full-size two-story test frame modeled from existing domestic RC structures with non-seismic details was subjected to pseudo-dynamic testing. As a result, the effect of the CFT-MF system, when applied to existing RC structures, was examined and verified, especially as to its seismic retrofitting performance, i.e., restoring force characteristics, stiffness reinforcement, and seismic response control. In addition, based on the pseudo-dynamic testing results, a restoring force characteristics model was proposed to implement non-linear dynamic analysis of a structure retrofitted with the CFT-MF system (i.e., the test frame). Finally, based on the proposed restoring force characteristics, non-linear dynamic analysis was conducted, and the results were compared with those obtained by the pseudo-dynamic tests. The results showed that the RC frame (building) with no retrofitting measures applied underwent shear failure at a seismic intensity of 200 cm/s2, the threshold applied in seismic design in Korea. In contrast, in the frame (building) retrofitted with the CFT-MF system, only minor earthquake damage was observed, and even when the maximum seismic intensity (300 cm/s2) that may occur in Korean was applied, small-scale damage was observed. These results confirmed the validity of the seismic retrofitting method based on the CFT-MF system developed in the present study. The non-linear dynamic analysis and the pseudo-dynamic test showed similar results, with an average deviation of 10% or less in seismic response load and displacement.

Seismic Performance of Two-story RC Frame Retrofitted Using External Steel Frame Equipped with Length-adjustment Device by Pseudodynamic Test

ABSTRACT Seismic retrofitting of exiting building structures is a technical and social issue aimed as earthquake risk mitigation. In this study, a new technique for seismic retrofitting via the attachment of an external steel frame with length-adjustment control box (ESFLC) was developed to strengthen medium-to-low-rise reinforced concrete (RC) buildings. The developed method, categorized as a strength design approach, can be used to perform seismic strengthening construction while residents continue to live within the building, exhibiting excellent constructability because a control box is applied as a length-adjustment device to cope with errors in the field associated with assembly works between the existing structure and reinforcing frame. Two full-size two-story RC frame specimens were designed based on an existing Korean RC building without seismic details; one control specimen and one specimen strengthened with the ESFLC system were used. Pseudodynamic tests were carried out to verify the effects of seismic retrofitting in terms of the maximum response strength, response displacement, and degree of earthquake damage compared with a control RC frame. Nonlinear dynamic analysis was also conducted based on the material properties of the test specimens, including mathematical models that represent the nonlinear hysteresis of the used structural members, to compare the results of the pseudodynamic tests. Test results revealed that the proposed ESFLC strengthening method, externally attached to the existing RC frame, effectively increased the lateral ultimate strength, resulting in reduced response displacement of RC structures under large-scale earthquake conditions. The nonlinear dynamic analysis and test results were in reasonable agreement.

Experimental and parametric investigation on elastoplastic seismic response of CFST battened built-up columns

Previous studies have proven that CFST (concrete-filled steel tube) battened built-up columns (CFST-BBCs) exhibit good hysteresis energy dissipation capacity and deformation capacity under lateral cyclic repeated loading. To further understand the elastoplastic seismic response characteristics of such composite structures under strong earthquakes, two pseudo-dynamic tests of 1/8-scaled CFST-BBC pier specimens were first performed. The acceleration records obtained in the 1995 Kobe Earthquake and the 2008 Wenchuan Earthquake were used to investigate how ground motion intensity, ground motion characteristics, and aftershocks affect the seismic response of the CFST-BBC pier. Meanwhile, an extensive time-history analysis of 17 fiber-based finite element models (FFEMs) under 20 different ground motions was performed to reveal the influence of the ground motion intensity, the same-intensity aftershock, and the main structural parameters on the elastoplastic seismic response of the CFST-BBC pier. Finally, a two-stage checking method suitable for the seismic performance of the CFST-BBC pier under the E1-level frequent earthquake and the E2-level rare earthquake was proposed. Verified by experimental and FFEM analysis results, the proposed checking method can accurately and effectively evaluate the strength and deformation capacity of the CFST-BBC piers under strong earthquakes.

Numerical Analysis of In-plane Behaviour of Masonry Infilled Rc Frames Using Macro And Micro Models

A number of simplified methodologies have been proposed aiming at preparing numerical tools suitable for engineering application, to predict the nonlinear seismic behavior of infilled frame structures. In this paper, a 2D discrete macro element model (DMEM) for the simulation of the in-plane behavior of RC frames with infill walls, is presented, validated with an experimental result that investigate the influence of infill masonry, and evaluated with a proposed Finite Element model (FEM). In this model, the frame members are modeled by beam-column elements with lumped plasticity, while the infills contribution are modeled by plane discrete-element. As an extended study, a 2D prototype of multistory frame building, for which the results of pseudo dynamic tests are available, is investigated. The ability of the considered DMEM to predict the in-plane behavior of infill masonry elements is investigated, the merits and drawbacks are highlighted.

Seismic Behavior of Moment-Resisting Frames with Conventional and Innovative Connections

In the last few decades, increasing efforts have been devoted to the development of beam-to-column connections able to accommodate the local ductility demand dissipating, contemporaneously, the seismic input energy. Among the typologies proposed, the so-called RBS (Reduced Beam Section) has gained wide acceptance in the construction market, leading to easy-to-construct and cost-effective solutions. As an alternative, new proposals based on the inclusion of friction devices in beam-to-column joints have recently been made. Such a practice has the merit, in case of destructive events, of exhibiting wide and stable hysteretic cycles concentrating damage in elements that undergo only minor yielding. Both RBS and friction joints have been widely studied, carrying out experimental tests on sub-assemblies investigating their cyclic rotational response. Nevertheless, the available experimental results on full-scale structures equipped with these connections are still quite limited. This is the reason why two experimental campaigns aimed at performing pseudo-dynamic testing of a full-scale two-storey steel building equipped with RBS and friction connections have been planned at the STRENGTH (STRuctural ENGineering Test Hall) Laboratory of the University of Salerno. The first experimental campaign with the structure equipped with RBSs has already been performed; the connections showed higher resistance than expected, and exhibited brittle fracture due to cyclic fatigue. The second campaign has not yet been carried out, but in this paper the blind analysis of the supposed behavior is reported. It is expected that the friction joints allow to dissipate the seismic input energy without any structural damage in the members, but only through the friction pads of the devices, which can be easily replaced at the end of a severe seismic event.

Pseudo‐dynamic and quasi‐static testing of hinged truss with all‐steel buckling‐restrained braces at base

AbstractHinged truss with buckling‐restrained braces at base (HTBB) is composed of a rocking steel braced frame system and two replaceable all‐steel buckling‐restrained braces (BRBs) installed symmetrically on both sides at the bottom of the rocking steel braced frame. BRBs are used as hysteretic energy‐dissipating devices and damage is concentrated in BRBs. The rocking steel braced frame remains in an elastic state to control the deformation mode of the structure. Pseudodynamic testing and quasi‐static testing were conducted on a 1/3‐scale HTBB test specimen to investigate its seismic performance. The test program also includes the retrofitting process and replacement process. Pseudodynamic testing revealed that the HTBB effectively controlled the deformation pattern. The quasi‐static cyclic testing demonstrated that the system behaved in a ductile and stable manner with no strength degradation, even up to 2.5% roof drift. The damage was concentrated in the BRBs, and no damage to the hinged truss was observed throughout the testing. The failure was governed by the fracture of the BRBs. The effectiveness of the displacement‐controlled retrofitting solutions was verified and the function of the test specimen can be restored by replacing the damaged BRBs, which indicated that HTBB belongs to a resilient structural system. Finally, a finite‐element model was developed to simulate the seismic response of the test specimen. Comparisons showed good agreement between the numerical results and the pseudodynamic test results.

Effect of early age drying shrinkage on the seismic response of RC structures

Reinforced Concrete (RC) structures get damaged over time due to many factors: thermal conditions, chemical attacks, shrinkage, creep, carbonation, corrosion, etc. This damaging process starts at early-age and continues with structure aging. Early age damage can have a significant impact on the dynamic behavior of reinforced concrete structures. In fact, the natural frequency of a structure, which is a design parameter can be highly reduced due to this damage. In order to quantify the impact of early-age damage (0 to 28 days) on the seismic response of a reinforced concrete structure, this thesis combined both numerical modeling and pseudo-dynamic tests on two types of RC portal frames. The first one was kept in endogenous conditions (water exchange with the surrounding environment was prevented) during its early age period in a way to limit drying effects leading to cracks. As for the second one, it was kept in non-endogenous conditions (possibility of water exchange with the surrounding environment) similar to construction site conditions, which induced an initial damage (cracks apparition) due to a more important drying shrinkage. Both types of RC portal frames were subjected after their early age period to the same seismic loading using pseudodynamic tests. On the one hand, this manuscript presents the experimental results obtained through the use of pseudodynamic tests in order to evaluate the behavior of the two types of RC structures under a moderate intensity earthquake. The structures were instrumented using optical fiber sensors, displacement and load sensors, velocimeters and monitored using Digital Image Correlation. On the other hand, the enhanced multifiber beam model that was developed for the portal frames in order to follow their early age damage and to determine their static and dynamic behavior while accounting for their early age effects is presented. In this numerical model, shrinkage and concrete thermal deformations are calculated and then introduced as inputs of a coupled damage model accounting for creep and mechanical deformations. Such model was validated by comparing its results to the ones obtained experimentally, which made it possible to evaluate the evolution of frequency content of the two types of structures during early age and to quantify their difference of behavior in the non-linear domain. Work conducted within this thesis thus allowed proposing a complete model for reinforced concrete structures that can be used in order to follow their damage evolution from casting until being subjected to a seismic load and to quantify their seismic vulnerability.

Pseudo-dynamic test investigation of recycled concrete-encased steel frame

This paper primarily focused on the seismic capacity of recycled concrete-encased steel (RCES) frame structure. A two-span three-storied RCES frame which is at 1:2.5 scale was conducted to investigate the acceleration time-history curves, acceleration amplification factors, peak restoring force and displacement, energy dissipation capacity, displacement time-history curves, bearing capacity, stiffness degradation and seismic performance evaluation during experiment. Based on the date analyzed compared with other structures, the hysteretic energy dissipation of RCES structure is better than the common reinforced concrete frame but similar to steel reinforced concrete. The pseudo-dynamic analysis method was adopted in this test. Taft, El Centro and Lanzhou synthesized wave were chosen as the input excitations. It is found that RCES structures show good seismic performance during the test. The beam is yield earlier than column, and the strain of node core area is small. The results indicate that the design of RCES frame meets the requirement of “strong column weak beam” and “strong node and strong anchorage”.

The Design of a Real-Scale Steel Moment-Resisting Frame for Pseudo-Dynamic Earthquake Testing

Background: Forthe reliable prediction of the non-linear response of structures, severe seismic events have proven to be a challenging task. Although much non-linear analysis software exists, the accuracy of the results depends on the assumptions made in the characterization of the members. Typically, the analytical models are calibrated using experimental observations. With this scope, experimental research remains the most reliable mean for the assessment of the seismic performance of structures, and it is crucial to target the development of new analytical models and design methods. Objective: Quasi-static tests can provide information on the non-linear behaviour of subassemblies, but it is often difficult to relate the imposed force or displacement histories to those that might occur during an earthquake. The pseudo-dynamic method combines an on-line computer simulation with experimental information about the tested structure, providing the application of realistic dynamic response histories. In this paper, the preliminary analysis and the design of a pseudo-dynamic testing facility for the experimental study of a real scale two storeys-two bays steel MRF, with classical and innovative joint details, are shown. Methods: Pushover and Incremental Dynamic Analyses carried out with Seismostruct software estimate the forces and displacements expected at each storey for the selected ground motions. These analyses have been performed by varying the structural detail of the beam-to-column connections. Results / Conclusion: In this paper, the analytical prediction of the performance of two bays-two storeys steel frames equipped with different solutions of beam-to-column joints is focused. Based on the performed analyses, it has been recognized that steel frames with partial strength joints can provide satisfactory performance under severe seismic actions provided that the joints are adequately designed.

Pseudodynamic Testing of Buildings Retrofitted with External Steel Reinforced Concrete Frames to Increase Lateral Strength for Earthquake Damage Prevention

In this study, a new technique for seismic retrofitting via the attachment of an “external steel reinforced concrete frame” (ESRCF) system was developed to strengthen medium-to-low-rise reinforced concrete (RC) buildings. Two methods (bolting and welding) were developed to connect existing RC frames and external strengthening elements; these methods are technically and practically suited to various construction conditions. The retrofitting method developed in this study can be used to perform seismic strengthening construction, while residents continue to live within the building. The method is categorized as a “strength design approach” implemented via retrofitting, allowing the lateral ultimate load capacity of RC buildings, whose failure mode is shear, to be increased easily. Test specimens were designed based on an existing RC building in Korea lacking seismic data and then strengthened using the ESRCF system. Pseudodynamic and cyclic loading tests were conducted to verify the effects of seismic retrofitting. In total, four RC frame specimens were prepared: one nonstrengthened control specimen for the cyclic loading test, one nonstrengthened control specimen, one specimen strengthened with a welded ESRCF system, and one specimen strengthened with a bolted ESRCF system for the pseudodynamic test. The earthquake response behavior with use of the proposed method, in terms of the maximum response strength, response displacement, and degree of earthquake damage, is compared with a control RC frame. The test results indicated that both the bolting and welding methods used for connecting the existing RC frame to the ESRCF effectively increased the lateral ultimate strength, resulting in reduced response displacement of building structures under large-scale earthquake conditions.

Steel Structures Research Update: Self-Centering Column Base Connections with Friction Dampers

Recent work on a self-centering column base connection with friction dampers is highlighted. This research is a collaborative effort by Senior Researcher Massimo Latour and Professor Gianvittorio Rizzano from the University of Salerno, Italy, and Professors Aldina Santiago and Luis Simões da Silva of the University of Coimbra, Portugal. The Salerno-Coimbra team has developed an alternative self-centering column base solution to minimize initial costs and economic losses. Specific objectives are to limit damage and residual drifts, with connection components that are easy to repair or replace if needed. The self-centering column base has been validated through quasi-static cyclic testing and pseudo-dynamic testing. The self-centering connection has also been investigated through numerical time-history analyses of moment-resisting frames comparing conventional, fixed column bases to self-centering column bases. Some highlights of the research are presented.

Pseudodynamic testing of a full-size two-story reinforced concrete frame retrofitted with an H-section steel frame installed using a length-adjustment control box

In this study, to overcome the construction drawbacks of conventional seismic retrofitting techniques, we proposed a new H-section steel frame (HSF) system for seismic strengthening of existing medium-to-low-rise reinforced concrete (RC) buildings. This HSF strengthening method exhibits excellent constructability because a control box is applied as a length adjustment device to cope with errors in the field associated with assembly works between the existing structure and reinforcing frame. The method represents a strength design approach implemented via retrofitting, to easily increase the ultimate lateral load capacity of RC buildings lacking seismic data, which exhibit shear failure. Two full-size two-story RC frame specimens were designed based on an existing RC building in Korea lacking seismic data, and then strengthened using the HSF system; thus, one control specimen and one specimen strengthened with the HSF system were used. Pseudodynamic tests were conducted to verify the effects of seismic retrofitting, and the earthquake response behavior with use of the proposed method, in terms of the maximum response strength, response displacement, and degree of earthquake damage compared with a control RC frame. Nonlinear dynamic analysis was performed based on the material properties of the test specimens, including a mathematical nonlinear hysteresis model to compare the results of the pseudodynamic tests. Test results revealed that the proposed HSF strengthening method, internally applied to the RC frame, effectively increased the lateral ultimate strength, resulting in reduced response displacement of RC structures under large-scale earthquake conditions. The nonlinear dynamic analysis and test results were in good agreement.

유사동적 실험에 의한 카고메트러스 삽입 콘크리트 패널 날개벽으로 내진보강 된 실물 2층 철근콘크리트 골조의 내진성능평가

본 연구에서는 기존 강도증진형 내진보강법의 단점을 보완ㆍ개선할 수 있는 새로운 개념의 내진보강법인 카고메트러스 삽입 콘크리트 패널(Kagome Concrete Panel, KCP) 날개벽 내진보강공법을 제안하였다. KCP 날개벽 내진보강법은 패널형식으로 접합부 시공성이 탁월하며, 특히 필요 내진보강량 산정이 간편한 전형적인 강도증진형으로 전단파괴가 지배적인 비내진상세를 가지는 국내 R/C 건물에는 내력확보가 용이한 내진보강공법이다. 본 연구에서 제안한 KCP 날개벽 공법의 유용성을 검증할 목적으로 기존 비내진상세를 가지는 R/C 학교건물을 바탕으로 한 실물 2층 골조 실험체를 대상으로 유사동적 실험을 하였으며, 동시에 내진보강 효과를 검토하였다. 그 결과, 국내 내진설계용 지진 수준인 300 gal 지진 규모에서 무보강 골조는 전단파괴를 하였지만, KCP 날개벽 내진보강법으로 보강한 골조는 소규모 지진피해가 예상되었으며, 대규모 지진을 상정한 400 gal 경우에도 중규모 정도의 지진피해가 예상되어 본 연구에서 개발한 KCP 날개벽 내진보강법의 유효성이 검증되었다고 사료된다.

Pseudo-dynamic testing of a full-scale two-storey steel building with RBS connections

The paramount role of beam-to-column joints on the seismic response of MRFs is universally recognised and many studies have been devoted to the improvement of their ductility and energy dissipation capacity, mostly after the seismic events of Northridge and Kobe. Nevertheless, while much experimental work has been already carried out on the seismic behaviour of beam-to-column sub-assemblages, the available experimental results on full-scale structures are still quite limited.Aiming to provide a contribution to fill this knowledge gap, an experimental program has been planned at the STRENGTH Laboratory of the University of Salerno concerning the pseudo-dynamic testing of a full-scale two-storey steel building equipped with five different connection typologies.In this paper, the results of the first series of tests, dealing with MRFs with RBS connections, are presented. The mock-up has been subjected to a sequence of seven accelerograms and the results have shown that, if properly designed, RBS connections provide large energy dissipation capacity and plastic rotation supply. Nevertheless, the failure of welds due to damage accumulation can be still possible, even adopting full penetration butt joint welding details conforming to Eurocode 3 and Eurocode 8 provisions.The test results are complemented with a numerical model developed with the software SeismoStruct. The comparisons between the numerical simulations and the experimental results show that the applied mixed distributed and concentrated plasticity approach, based on the adoption of phenomenological spring models, can capture accurately the global response of the structure, but it predicts with lower accuracy the local response parameters.

Hybrid simulation: An early history

SummaryThis historical note reports on the early days of the development of an experimental method called “hybrid simulation.” As background, the seeds of this concept, initiated in the early 1970s by Japanese researchers, are presented first, followed by initial efforts (regarded as Stage I) to realize the concept of hybrid simulation and its first applications to explore the seismic performance of structures. The initial research in this now‐seminal field of earthquake engineering began in the early 1970s by Koichi Takanashi and his coworkers at the Institute of Industrial Science, the University of Tokyo. Their highly notable efforts in laying the groundwork for hybrid simulation occurred in the mid‐1970s through the early 1980s by Takanashi (for steel structures) and Tsuneo Okada (for RC structures). These two men and their coworkers first applied hybrid simulation to explore the seismic behavior, performance, and design of various types of building structures. In Stage I, this method was called “the on‐line computer‐controlled test” or “pseudo dynamic test” because the unique feature of the method was the combined test and simulation and the intentional slow loading in the test. Extension of the scope and application of hybrid simulation occurred largely between the early 1980s and the early 1990s (regarded as Stage II) in conjunction with the United States–Japan joint research project. A few notable efforts made around that period are touched upon briefly, including error propagation and suppression in multi‐degree‐of‐freedom hybrid simulation, application of the substructure methodology to hybrid simulation, and real‐time hybrid simulation.

Strengthening of reinforced concrete frames with engineered cementitious composite panels

Infill walls in reinforced concrete frames are susceptible to failure owing to their brittle nature. Their interaction with boundary columns during earthquakes may also cause shear damage in the columns. It is crucial to employ effective seismic strengthening strategies in order to mitigate the seismic risk induced by the infill walls. In this study, a new strengthening technique, conducted by bonding engineered cementitious composite (ECC) precast panels onto infill walls, was investigated. Three reinforced concrete frames, termed bare frame, infilled frame and strengthened frame, were tested by using the pseudo-dynamic testing method. The test specimens were three-storey, three-bay, half-scaled frames with the central bay having hollow clay brick infill walls. The specimens were subjected to three consecutive ground motions scaled to represent earthquakes with return periods of 144, 475 and 2475 years. The experimental results were compared to observe the influence of the infill walls on the reinforced concrete frames, and to demonstrate the performance of the proposed strengthening technique. It was found that application of ECC panels significantly increased the frame strength and stiffness while allowing the system to have a displacement ductility of about four.

Pseudo-dynamic response and analytical evaluation of blind bolted CFT frames with BRBs

This paper presents the experimental and analytical studies on the blind bolted end plate concrete-filled steel tube (CFT) composite frames with buckling-restrained braces (BRBs). A series of pseudo-dynamic tests (PDTs) on two 2/3-scaled two-story, one-bay blind bolted end plate CFT (BECFT) composite frames with BRBs showed that the novel dual system exhibited good hysteretic behavior and high ductility. The moment capacity, initial rotational stiffness, rotation capacity and the mathematical moment-rotation model of a BECFT composite joint were systematically analyzed and modified to some extent. Meanwhile, the shear force-deformation relation of a CFT panel zone was suggested and checked for its applicability. Furthermore, the macroscopic finite element (FE) model incorporating semi-rigid characteristic of the joint and shear response of the panel zone was developed by OpenSees program. The numerical analytical results would match better with experimental data when the FE model took the gusset plate stiffness into account in comparison with other models neglecting this case. Both experimental and FE analytical results indicated that the BRBs were in elastic state to provide great lateral stiffness and resistance under small earthquakes, and they yield first to stably dissipate energy under severe earthquakes. The combination of BECFT composite frames with BRBs will extend the feasibility of the novel dual system in high- or even super high-rise buildings.

Laboratory Experiments for the Force and Load with Pseudo-Dynamic Test: Ex-vivo Study for the Manual Therapy

Background: Because of the lack of accurate values for applied forces in manual therapy, manual therapists relies on the magnitude of the individual’s perception during applying the force. However, excessive loading maneuvers carry risks for patients. Objective: To establish the relationship between the maximal force applied to swine skin with the specific region, sex, and baseline parameters of the sub­ject. Design: Ex-vivo Study and laboratory Experimental research Methods: 3.5 kg of Korean pork sirloin that is a piece of swine was handled and it was set 3 dimensions; #A; #B; #C. Forty-seven participants who has no experience in physical therapy randomly carried out the experiment, indicated to push each place of the pressure spots with same posture and process under supervision from the instructor who has over 15 years of manual thera­py, and we measured the pressure force in each time. Results: The biggest pressure force was recorded in spot #A, and #B was represented after #C. Pressure on #A showed certain statistic relation with height (r=.317, p<.05) and weight (r=.434, p<.01); pressure on #B showed cer­tain relation which has statistical meaning with only height (r=.401, p<.01); pressure on #C emerged to have statistic relationship with height (r=.308, p< .05)and weight (r=.428, p<.01). The age aspect revealed relation with pressure on #A, #B and #C, but that was not statistically significant. Conclusions: It can be inferred that there is the most loss of pressure in the area where cartilage is like an island in the middle.