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The ten-story full-scale shaking table tests conducted in 2015 and 2018 are simulated by analytical models such as being used in design practice or proposed in recent research and compared with the test data to simulate 1) the effective slab width on the beam capacities and 2) the base sliding and uplifting behavior. Three-dimensional pushover analysis used in the design practice of Japan was applied for the shake table tests with fixed base by varying the effective slab width on the beam to simulate the load-displacement relations and the lateral load carrying capacity in the tests. The effectiveness of slab and transverse beams was also evaluated in detail by the analysis with Timoshenko fiber beam element model applied partially for an outer span end in the wall direction. The analytical strains of slab reinforcement at the outer span end were compared with the measured in the tests. Three-dimensional nonlinear dynamic frame analyses with sliding base foundation models were carried out to simulate the responses of the superstructure and the sliding drift. Different types of simple base models were used where the two-way sliding and axial-shear interaction were considered at the center of the specimen while the horizontal base rotation was neglected. The response reduction of the superstructure owing to the sliding base could be approximated by either of base models, while still large discrepancy was observed in the sliding drifts among the test and the analyses.

The effects of floor slabs on the flexural strength of beams in reinforced concrete buildings under seismic action were verified through tests of frame assembly specimens. A series of experimental and analytical investigations were conducted from 2010 to 2014 in order to further validate the current design practices in Japan. Loading methods in the past beam component tests were reviewed with probable effects of floor slabs. A special loading set-up was used for the frame assembly specimens consisting of four columns and four beams with lengths of one span and two half spans in two directions. The four columns were loaded laterally and independently at mid-height of the upper storey and supported at mid-height of the lower storey with pin-fixed and pin-roller so that axial elongation of the beams and slab would not be constrained by the lateral forces. It has been found from these new loading tests that the tensile stresses in the floor slab reinforcing bars are generally uniform at the beam critical sections and up to the full slab width for the flexural strength when the slab is subjected to tension bending around one percent storey drift, which is much wider than assumed in the current design evaluation.

Static loading tests on two full-scale reinforced concrete buildings were conducted at Building Research Institute in 2014 and 2015 to verify the effectiveness of damage control design utilizing walls. The tested buildings were five-storeys high with two bays in the direction of loading. The 2014 specimen was a moment resisting frame consisting of beams and columns with wing walls. The 2015 specimen contained wing walls, spandrels and hanging walls attached to the columns and beams. The measured strengths were much higher than the calculated strength of the bare frame without these walls. The hysteretic curves showed ductile behaviour in the 2014 specimen until ultimate drift, while strength deterioration was observed in the 2015 specimen. From the cracking pattern and the storey drift distributions within the specimens, the first specimen formed a beam sway mechanism, and the second specimen formed a mixed mechanism with column yielding between the 1st to 3rd storeys. The residual cracks of the specimens were generally wider due to the concentration of the plastic hinge region, although the damage was evaluated as slight at 0.33% drift and as minor at 0.75% based on the residual energy capacity. Damage grades evaluated from the residual energy capacity were obviously smaller than the damage grades evaluated from the residual crack widths in accordance with the damage evaluation guidelines.

In order to use a damaged building continuously after earthquake, owners and/or stakeholders need to understand residual seismic capacity of the building. In Japan, a method to evaluate residual seismic capacity for damaged buildings had been developed. In order to evaluate residual seismic capacity of damaged building, the damage level of structural elements should be evaluated properly. This paper presents the results of damage analysis based on experimental data obtained from a full-scale static loading test [1] on a five-story reinforced concrete building tested at Building Research Institute. The damage rating for the specimens evaluated by the residual seismic capacity concept [3] was ”Moderate” or ”Heavy” at 0.5% and 1% building drift angle despite the structure maintaining horizontal load carrying capacity. This implies that the applied method gives a conservative result for ductile buildings, such as relatively new moment resisting frames designed after 1981. In order to apply the method used in this paper to new buildings, the damage evaluation method for structural elements should be advanced more in the future.

In this paper, results are presented from shaking-table tests of a full-scale 10-story reinforced-concrete structure to confirm the behavior of a free-standing system with a base that permits both sliding and uplifting. The purpose of this system is to use the seismic resistance of the structure during a small or medium earthquake and a sliding and uplifting behavior of the free-standing system during a large earthquake. Cast-iron plates were installed on the grade beams of the lower part of the specimen building to generate a low friction coefficient. Thus, the specimen building should be able to move sideways during large earthquakes, although the specimen building should not move sideways during small earthquakes. In the tests, the specimen building was moved sideways during tests with JMA-Kobe 25%, 50%, and 100% amplitude excitations but not during that with JMA-Kobe 10% amplitude excitation, and the specimen building was uplifted at one of its corners for all amplitude excitations. The base sliding displacement was 84–189 mm, and the corner uplift was 5–40 mm. The sliding and uplift behavior led to small maximum inter-story drift ratios, and these behaviors did not increase the base overturning moments. Thus, allowing sliding and uplifting behavior can reduce building damage in an extremely large earthquake.

A series of static and seismic loading tests of reinforced concrete frame assemblies were conducted in 2010, 2012, 2013 and 2014 to identify the effects of slab for evaluation of seismic capacities of reinforced concrete buildings as part of national research projects for review of the technical standards on seismic design practices in Japan. Two-fifth or half scale seven specimens were tested representing three-dimensional reinforced concrete beam-yielding frames with floor slab. A special loading set-up was invented and used to simulate the boundary conditions of the medium-story frame so that the axial elongation of the beams would not be constrained by the reaction supports consisting of pin-fixed and pin-roller. It was generally found from the series of tests and analyses that the slab reinforcing bars were increasing almost uniformly through the whole slab width and was fully effective to the flexural strength of the beams at around one percent story drift. The observed and calculated beam strengths with the full width of slab was much higher than those with the effective slab reinforcing bars assumed in the current design practice.

SUMMARY A full-scale shake table test on a six-story reinforced concrete wall frame structure was carried out at E-Defense, the world's largest three-dimensional earthquake simulation facility, in January 2006. Story collapse induced from shear failure of shear critical members (e.g., short columns and shear walls) was successfully produced in the test. Insights gained into the seismic behavior of a full-scale specimen subjected to severe earthquake loads are presented in this paper. To reproduce the collapse process of the specimen and evaluate the ability of analytical tools to predict post-peak behavior, numerical simulation was also conducted, modeling the seismic behavior of each member with different kinds of models, which differ primarily in their ability to simulate strength decay. Simulated results showed good agreement with the strength-degrading features observed in post-peak regions where shear failure of members and concentrated deformation occurred in the first story. The simulated results tended to underestimate observed values such as maximum base shear and maximum displacement. The effects of member model characteristics, torsional response, and earthquake load dimensions (i.e., three-dimensional effects) on the collapse process of the specimen were also investigated through comprehensive dynamic analyses, which highlighted the following seismic characteristics of the full-scale specimen: (i) a model that is incapable of simulating a specimen's strength deterioration is inadequate to simulate the post-peak behavior of the specimen; (ii) the torsional response generated from uniaxial eccentricity in the longitudinal direction was more significant in the elastic range than in the inelastic range; and (iii) three-dimensional earthquake loads (X–Y–Z axes) generated larger maximum displacement than any other loading cases such as two-dimensional (X–Y or Y–Z axes) or one-dimensional (Y axis only) excitation. Copyright © 2011 John Wiley & Sons, Ltd.

The response reduction of reinforced concrete (RC) building structures due to soil-structural interaction has been discussed generally using simplified models idealized with an equivalent elastic sway spring, because the nonlinear characteristics and frequency dependent response of surrounding soils are not well quantified in large inelastic range. Aside from these nonlinear soil deformations, the response of RC structures on spread foundation could decrease with nonlinear base slip behavior, if the foundation base shear exceeds the friction strength at the base of the footings. The behavior has been verified through a full-scale shake table test of RC buildings with spread foundation on the concrete slab. In this paper, the upper-bound response of RC structures with a simple nonlinear sway spring is estimated generally based on dynamics theory. The potential energy of the structure is conserved during base slip, so that the maximum response of the structure during base slip is to be limited from the velocity and restoring force when the base starts to slip. The maximum velocity can be evaluated on the assumption that the maximum input acceleration acts on the structure during the preceding period of base non-slipping behavior. Therefore, the maximum restoring force can be estimated using the maximum input acceleration, the base friction coefficient, and the mass ratio of the upper structure and the foundation. The accuracy of the theoretical estimation was verified through the nonlinear responses of the models with wide range of parameters.

Tests on reinforced columns with wing wall s were conducted in 2010 to investigate the flexural deformability following the shear tests in the previous years. The effects of the moment-to-shear ratios of loading, the reinforcement details and the width and length of the wing wall s on the flexural deformability were investigated. The specimens with thin wing wall s showed strength decay after the ultimate strength in flexure, due to the compression failure of concrete and buckling of the re-bars at the wall ends under the larger deformation amplitudes, while the specimens with thick wing wall s showed much less strength decay generally. If the edge was well confined, the strength decay was much smaller. All specimens were ductile and stable in flexural failure mode up to the maximum loading drift level. The damage to the column could relatively be relieved owing to the inelastic energy dissipation by the wing wall s. The ultimate strength and deformability are formulated for practical calculation based on a flexural theory and are compared with the test results, by which fair correlations are obtained. A simple formula on the deformability is derived based on the theory, by which the deformability rank of the member may be specified in the current code of seismic design.

Typical damages to reinforced concrete buildings, both by the ground motions and the tsunami waves, are outlined in this section. The report herein is based primarily on the field survey of the AIJ members and collected through the members of the Reinforced Concrete Steering Committee of AIJ. The typical damages to reinforced concrete buildings are described below through the reports on the buildings selected and available for detailed survey. The damage reports below are translated selectively from the Chap. 6, Sect. 6.2 of AIJ report in Japanese version, which contains more photos and figures, especially on the structural plans as well as the damage rate evaluation of members. The reports on the buildings below are arranged as from the Japanese version: (1) school buildings located from north to south (Iwate, Miyagi, Fukushima and Kanto areas), (2) government offices, (3) residential buildings.

Owing to systematic and dense seismic observation networks, extreme ground motions have been recorded in recent major earthquakes with high velocity or high acceleration far exceeding the conventional design code level. At the same time, most of reinforced concrete (RC) building structures in Japan survived these severe motions, probably because of higher capacity than design requirements or of input loss at the base. The authors have conducted shake table tests on full-scale RC buildings with flexible foundation at E-Defense to verify the input loss at the base. The test results are outlined in this paper, where the obvious reduction of damage to the building structure was observed owing to the slip behavior at the base. The results show that it is feasible to and apply in practice a fail-safe system against possible and yet unseen future extreme motions, by incorporating the slip behaviour positively to control damage or ensure safety.

Unique foundations consisting of stones wrapped in vegetable fiber bags called shicra (“woven”) have been found in many Pacific coast ruins constructed about 5,000 years ago as shrines in Peru. A shaking table test was conducted to investigate earthquake response properties of these shicra foundations. Results showed that in base isolation performance, shicra foundations “rolled” during earthquake vibration the same as in the case of roller base isolation systems.