In Japan, wood has been used for many years as a building material. On the other hand, wet condition is the strongest factor to promote degradation of wood, and it may cause corrosion and damage to termite and so on. These biological decompositions proceed more rapidly than ultraviolet deterioration and there exists a significant fatal deterioration due to remarkable strength drop. Especially for valuable timber buildings that have existed since long ago, it is essential to achieve a permanent maintenance of the building by diagnosing the decrease of strength due to deterioration. However, except for important cultural assets, assessment of the durability of Japanese cultural heritage buildings is often entrusted to local public entities, and evaluation criteria detected by visual investigation is sometimes not accurate.
 In addition, when deterioration progresses only in the inside of wood, it is difficult to judge deterioration visually from outside, and, at present, a sufficient diagnostic method has not been studied. Furthermore, it is common that the restoration and refurbishment method currently implemented for the biodegradation of wooden buildings is to remove degraded parts and partially replace with new healthy wood. It is desirable to reinforce the original part as it is to restore the strength, but it has not been put into practical use yet.
 In this study, a basic experiment was carried out with the aim of proposing a member that was internally deteriorated due to termite's damage. Quantitative evaluation of this damage degree was proposed and the effect of reinforcing the inside part with resin and its non-destructive evaluation were verified.
 The findings obtained in this study are shown below.
 Detection of the internal deterioration of the artificial drilled degradation by the ultrasonic method was able to perform at about 30% of the defect by volume. Although it was difficult to detect the defect of about 10% by volume by the ultra-sonic method, the compressive strength is not markedly decreased. On the other hands, the clear reduction of the strength was observed at the rate of 30% defect the and the ultrasonic method successfully detected the pulse change. In addition, the strength improvement by filling resin was performed and the ultrasonic method successfully evaluated the defect. The relationship between the propagation velocity ratio by the ultrasonic method and the mass ratio was high. Similar results were obtained in the case of the deterioration by termites. Hence, the internal deterioration can be detected by the ultrasonic method. Meanwhile, improvement of the strength by resin filling was also increased the velocity of pulse of the ultrasonic. This might indicate that the strength improvement effect by the resin filling could be evaluated by ultrasonic method.
 Similar to the compression test with the reinforcement by resin filling, bending Young's modulus and bending load were partially improved and the effect could be evaluated by the ultrasonic surface method.
 In the future, as a practical research, authors will examine current improvement effect of bending strength, construction method such as resin selection and resin injection method. In addition, quantitative evaluation of resin filling degree and reinforcing effect by the ultrasonic wave propagation speed are considered to be necessary.

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 Simple non-linear response prediction method (stochastic RMS Method) is developed, subjected to the building excited by arbitrary shape spectrum input based on statistical equivalent linearization technique. In previous method, hysteretic characteristic is modeled by unit function independently its shape, and it is necessary to introduce nonlinearity term of system like coulomb slider into equation of motion except displacement and velocity. However, mixture of these term causes complication to solve equation, and is reason to use only white noise for input. The equation made with above process can't solve except explicit time history analysis. In this paper, equation of motion is made with only state variable express displacement and velocity to introduce displacement δa at reversal point as parameters. as equation of motion set simple, it is possible to use arbitrary shape spectrum. This method can adopt poly-linear hysteretic characteristic or MDOF system. Decision of this method is examined for 10 story model building compared with MCS (Monte Carlo Simulation).
 · For SDOF, difference of stochastic RMS method and MCS is under 20% for ductility factor 1~8.
 · For MDOF, when ductility factor is about 2, maximum difference of both method is about 20%. RMS value of story drift angle σ[Rmax] cause larger difference.
 ·Un-exceedance probability show same tendency.
 · Difference of time history response and stationary response is few. With use ordinary envelope function to time like this paper, both method is available.
 · When building has stiffness eccentricity, accuracy of stochastic RMS method decline at weak story. bat, response of other story slightly decline.
 CPU time to calculate about model building is 10~15 minutes by stochastic MCS, and 1~2 second by stochastic RMS method. RMS method is superior with MCS for time to calculate.

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 In the event of an earthquake that could cause damage to the house, various institutions are conducting survey, such as emergency risk determination, on the damage level of houses for different purposes. Though both of these investigations differ in purpose and criteria, they are indispensable for restoration and reconstruction of housing and residents' lives, and accurate and stable survey results are required. However, in the survey based on visual, it is impossible to avoid variations and bias of judgment by the implementer. In addition, when many houses suffer damage, it is essential to shorten the investigation time in order to respond promptly.
 Meanwhile, due to technological innovation in recent years, an acceleration sensor that can be applied to microtremor measurement has been developed. Main improvements are improvement of accuracy in the low frequency range due to high resolution and noise reduction, less burdensome transportation by weight reduction and ultra miniaturization, simplification of installation and measurement wirelessly, and cost reduction of the measurement system.
 In the review of these background, in this paper, for the purpose of disaster evaluation of low-rise housing by microtremor measurement directed to Japanese conventional wooden and light-gauge steel structure, the reduction rate of the primary natural frequency of the vibration table test f_m / f₀ (However, f₀: initial primary natural frequency, f_m: the primary natural frequency after excitation (earthquake)) was newly constructed. And by comparing and examining past evaluation formulas related to traditional wooden structure, the following knowledge was obtained.
 · Regarding each shaking table test of conventional wooden, light-gauge steel, and traditional wooden structure considered in this paper, regardless of the structure type, it is possible to unify the deformation dependence evaluation formula of the primary natural frequency decrease rate using a coefficient γ0.5m, which is γmax when (f_m/f₀)² is 0.5.
 · The coefficient α, relating to the decrease gradient to the maximum deformation angle of the reduction rate of the primary natural frequency, make it possible to improve the accuracy of the evaluation formula of the primary natural frequency decrease rate, between a micro deformation and the deformation angle 1/50rad, which is the criteria to determine the continued availability of houses.
 However, the findings obtained here are based on specific experimental results, and from now on, it is necessary to verify the validity of the evaluation formula with reference to the results of the actual shaking table experiment.

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 In this paper, we introduce shaking table test of a full-scale two-story structure with story deflection control system. The story deflection control system is a Linked Fluid Inertia Mass Damper we developed in the previous study. The purpose of the shaking table test is to verify that the seismic response control by Linked Fluid Inertia Mass Damper (LFIMD) works quite effectively for the real scale structure. The test frame is a light-gauge cold-formed steel frame consisting of walls with built in friction devices and CLT floor panels. The story height is the same as of actual structure. Walls in the shaking direction are equipped with friction devices. In addition, normal structural plywood shear walls are installed in the frame orthogonal to shaking direction to minimize deflection in that direction. We call this structure a basic frame. In this shaking table test, we compare the test results of basic frame and those of the frame with LFIMD.
 First, we study dynamic characteristics with/without the damper. Second vibration mode does not clearly appear and first vibration mode damping ratio increases by using the damper. The test results of basic frame show that the damage is likely to concentrate to 1st story. The tendency becomes more prominent as the yield strength ratio of the first story becomes smaller. On the other hand, the story deflection distribution will be quite uniform by using the damper. Important thing to note is that response acceleration may increase, but the maximum value is suppressed to no greater than 10 m/s².
 Next, we constructed an analytical model of the test frame to quantitatively evaluate the seismic response control effect by LFIMD. The friction device installed in shear wall of the main structure was simulated by tri-linear type load-deflection relation. Its validity was confirmed by incremental displacement analysis. And the mechanical properties of the damper were identified by comparing test results with those theoretically calculated results. Although viscous damping effect and inertia mass effect was the same as we had expected, link stiffness showed lower stiffness than that obtained in the pre-performance test. Time history response analysis showed that the dynamic analytical model using modified link stiffness can simulate the test results fairly well. We studied the seismic response control effect of installing LFIMD by using this model. Analytical results showed that viscous damping effect is effective in reducing response story deflection. Inertia mass effect is effective in reducing response acceleration. Link system is effective in preventing damage concentration. From the results above, it was clarified that Linked Fluid Inertia Mass Damper can exert high seismic response control effect by comprehensively exhibiting each seismic response control effect.

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 This study presents a new control system, which is an extended EID (EEID) method, for active structural control (ASC) based on the equivalent-input-disturbance (EID) approach. This method considers both the absolute acceleration and relative displacement of a building. In the last few decades, some advanced control methods are also applied for ASC. Suppressing absolute acceleration is important to protect properties and people from a large earthquake. However, conventional EID control method only considered the relative displacement but not absolute acceleration. In contrast, EEID considers both the absolute acceleration and the displacement.
 Section 2 explains the EEID and EID method. This section shows the whole EEID control system, and how to calculate an EEID of a system.
 Section 3 considers the transfer function of EEID from the disturbance input channel to the state of the control system. This section shows the EEID system has two control parts, which are the feedforward and feedback control parts. The feedforward part consists of the observer and the low-pass filter and the feedback control part consists of the feedback controller gain and the control input matrix.
 Section 4 uses a single degree-of-freedom shear building model to compare the control performance of EID and EEID for a displacement and an absolute acceleration. This section explains that the observer gain of EID only adjusts the constant term of the transfer function of the disturbance to the displacement. In contrast, the observer gain of EEID not only influences the constant term but also the dynamic characteristic term.
 Section 5 shows the results of numerical examples. This section uses three models that ordinal frequencies are 0.5, 1.0 and 2.0 Hz to demonstrate the validity of EEID. The results show that the control performances for absolute acceleration of NC, FB, EID and EEID are almost all the same especially for low frequency. In contrast, the results of the frequency responses for the transfer function from the disturbance to the displacement shows that the control performance for displacement of EEID is much better than that of the NC, FB and EID. There is a trade-off between the absolute acceleration and the displacement in addition to the control performance for absolute acceleration of the EEID being the same as the EID. However, despite this, the control performance for the displacement of the EEID is much better than that of the EID.
 Section 6 is the conclusion of this paper. The advantages of EEID are as follow:
 1) EEID consists the two control parts, which are the feedforward and feedback control parts. Thus, the control performance for displacement of EEID is much better than that of the conventional feedback control system.
 2) The observer gain of EEID adjusts not only the constant term but also the dynamic characteristic term in the transfer function from the disturbance to the displacement. Thus, the control performance for displacement of EEID is much better than that of the EID.
 3) There is a trade-off between the control performance for the absolute acceleration and the displacement. The control performance for displacement of EEID is much better than that of the EID while the control performance for absolute acceleration of EEID is the same as the EID.

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 Distinctive pulse motions were recorded near the seismic faults in the source region of the main shock of the 2016 Kumamoto earthquake. Large-scale crustal deformation and surface ruptures occurred. The peak ground velocity in Nishihara Village exceeded 250 cm/s, this velocity was generated by a long-period pulse of approximately 3s. Mashiki town was situated within a severely damaged zone with a local range approximately 1 km wide. In order to clarify the relationship between the building damage and the pulse-type ground motions, it is important to clarify the generation mechanism of large-amplitude pulse-type ground motions, which greatly influence the response of various types of structures including super-high-rise and isolated buildings.
 In this study, we constructed a seismic source model of the main shock of the 2016 Kumamoto earthquake to simulate the corresponding strong ground motions, including those recorded in the vicinity of the seismic faults and in the building damage zone in Mashiki town.
 The conclusions of this study are summarized as follows:

 1) First, we examined the heterogeneous source model proposed by Hikima (2016). The correction spectrum was applied to compensate for the short-period range amplitude reduction and to incorporate the sub-fault rupture propagation into the calculation. Therefore, velocity waveforms at distant observation stations were simulated over the whole period. In the waveform inversion analysis, the effective frequency range is limited and Nishihara Village are not included, therefore, the large-amplitude pulses that have a period of approximately 1s recorded in Mashiki town and those recorded in Nishihara Village could not be reproduced.

 2) Second, we constructed a characterized fault model (Model-C1), comprising multiple SMGAs and LMGAs by referring to models proposed by SATOH (2017), Irikura et al. (2017) and Tanaka et al. (2017), respectively. The source process, including rupture from the bottom towards Mashiki town, was indispensable for generating large pulse waves with a period of 1s, as observed at the KiK-net Mashiki stations. However, the distribution of peak ground velocity in the fault-normal-direction line showed a peak in the North direction at the KiK-net Mashiki station; this distribution differed from the damage concentration area of the wooden houses.

 3) Third, using the above characterized fault model, long-period pulses with large amplitudes as observed at Nishihara Village were successfully simulated. Surface slip rupture due to the nearby LMGA and normal fault slip of the Idenoguchi faults, both of which are parallel to the main faults, were found to largely contribute to the long-period pulses that were recorded at the Nishihara Village.

 4) Fourth, in order to reproduce the distribution of the strong ground motions corresponding to the local damage area, we proposed another characterized fault model (Model-C2) in which the top of the SMGA was located at a relatively shallow area just under Mashiki town. Using this analysis, the pulse velocity in Mashiki town was simulated. However, the reproducibility of strong ground motion records at stations that are distant from the hypocenter is not sufficiently good.

 5) Finally, the distant observed ground motion records have been successfully reproduced in a broad area including the vicinity of the seismic faults through the combination of the heterogeneous fault model and the characterized fault model (Model-C2). The distribution of the strong ground motions corresponding to the local damage area in Mashiki town was also reproduced.

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 Among various methods for seismic retrofit, installation of shear wall composed of light weight blocks to existing frame is an effective approach in view of reduction of construction cost because they can resist compression (contact to wall) only and complex anchoring and/or welding is not necessary. However, shape of block in practical design tends to be regular due to simplicity in manufacturing process. The second author developed a method of shape optimization of latticed blocks based on ground structure approach. Since a nonlinear programming approach is used, very thin lattice members existed in the optimal solutions. To prevent this difficulty, a combinatorial method has been presented for layout optimization of blocks with given pattern. In both studies, location of the node is fixed, and the latticed block is discretized into beam element.
 This paper presents a new method of shape optimization of a shear wall consisting of latticed blocks, where the lattice members are discretized into plane stress shell elements and the location of node and the width of diagonal elements of latticed blocks are adopted as design variables, respectively. In the first phase of proposed method, the geometry of lattice is optimized with fixed topology and width of lattice members. In the second phase, the width of lattice members are optimized with fixed topology and geometry. Each phase is repeated alternatively, and the members with small width are removed to change the topology before restarting the first phase. In each phase, an optimization problem is formulated to maximize the lateral reaction force for specified inter-story drift angle. Simulated Annealing (SA) is used for solving the optimization problem. Moreover, to obtain various shapes, force density method is utilized to move the nodes without modifying topology. In this approach, force density is treated as an auxiliary parameter for arrangement of latticed element.
 Numerical examples are presented to demonstrate effectiveness of the proposed method. In numerical examples, it can be confirmed that various kinds of optimal solution are obtained. And it is shown that a truss frame which each member is arranged diagonally for smooth stress transmission through optimization process. Optimal solutions can resist the shear force 1.09-1.34 times larger than that of the initial shape. By using this proposed method, it can be confirmed that optimal solution can be archived maximizing the lateral reaction force.

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 In many large-span facilities, a structural type in which a large steel roof is installed on the lower RC frame, has been widely used. The conventional roof bearings connecting the roof to the lower RC frame, have often similar detail to that of an exposed column base. However, such roof bearings have frequently suffered severe damages, such as fracture or pull-out of anchor bolts and crash of base mortar, in great earthquake disasters. In the present study, two improvements from the conventional bearings were devised to avoid these damages and their effectiveness was examined through full-scale tests. One improvement was to insert a rubber plate between the base plate and base mortar. The rubber plate was intended to carry the horizontal shear stress due to earthquake response so that the shear and flexural deformation of anchor bolts could be avoided. Another was to introduce disc springs into the anchor bolts. This was to expand the elastic range of the anchor bolt and to avoid the loss of tension due to the bearing rotation as far as possible.
 In the tests, the bearing models were loaded by constant vertical and cyclic horizontal loads, together with introducing the initial tension to the four anchor bolts. Three tests (identified by the signs R29-s-d, R87-m-d and F87-m-d) were carried out where the presence of the rubber plate, base mortar and the loose hole for the anchor bolt was changed. A friction chemical coating was used to transmit shear stress between the base and rubber plates and between the rubber plate and base mortar.
 In the R29-s-d test, the rubber was inserted but the anchor-bolt hole was not loose so that the anchor bolts were directly subjected to the horizontal force. Moreover the base mortar was replaced to a thick steel plate. In the test, large rotation accompanying yield of the anchor bolts due to tension was observed.
 In the R87-m-d test, the anchor bolt holes were loose to avoid contact of the anchor bolts to the base and rubber plates. The horizontal force was carried by shear of the rubber plate so that the anchor bolts were subjected to only axial tension due to rotation of the bearing. This design intent was successful. Significant shear or flexural deformation of the anchor bolts and crash of base mortars were not observable.
 In the F87-m-d test, the rubber was replaced to a steel plate but the anchor bolt holes were loose. Without the rubber plate, the shear force was not absorbed by the shear deformation of the rubber so that the steel plate slid on the mortar. The mortar was also crushed by rotation of the steel plate.
 In the three tests, the rotations and horizontal loads at the axial yield of anchor bolt were almost same level. However, the presence of the rubber plate influenced on the horizontal behavior. In the R87-m-d test, where the shear force was resisted mainly by the rubber, the horizontal displacement was quite large.
 On the elastic shear stiffness, calculation by the theory for the rubber plate itself agreed well with the test results. On the rotational stiffness, a theoretical formulation was carried out considering the axial stiffness of the disk spring and the rotational stiffness of rubber plate. Good agreement was obtained between the calculation applying the derived equations and the results of the R87-m-d test.

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 Although tensile reinforcement is placed in three layers in deep R/C beams like foundation beams due to requirement of large stress, the AIJ standard¹⁾ does not provide how bond around deformed bars in third layer should be verified. In these days, loading tests of R/C beams with double layers of deformed bars were conducted. When shear cracks occurred at end regions of the beam subjected to anti-symmetric bending, bond stress became quite small in the cracked area. This behavior is called tension shift. However, when bars in the second layer were terminated in the span, the tension shift in the cut-off bars did not appear clearly. Meanwhile bond stress around the extreme layer was small in the range where the cut-off bars exist, and was large in other range where no bars remain in the second layer. While the experimental studies on double layered R/C beams have progressed, experimental tests on triple layered beams are limited. In the AIJ standard, the effective bond range must be reduced by subtracting the tension shift range from the embedment length of the bar. And the tension shift range is defined as the same length as effective depth of the beam. That tension shift range is not reasonable for cut-off bars in the deep beams. As mentioned above, triple layered arrangements are often chosen for the deep beams.

 In this study, anti-symmetric bending tests and FE analyses of R/C deep beams with triple layered arrangements were carried out in order to make clear the influence on bond behavior by terminating the bars in the span. Especially, tension shift in the cut-off bars around the beam end was focused on. Two foundation beam specimens were prepared. The tensile reinforcement was placed in three layers in the both beams. High-strength shear reinforcement and normal strength concrete were used for the specimens. The parameter of test was whether the bars in the third layer were terminated in the span or not. In discussion on the test and numerical results, where a previous test result⁷⁾ was added, an equilibrium model⁵⁾⁶⁾ between bond stress and shear reinforcement stress was used. In this model, it is assumed that moment of the tensile stress in shear reinforcement takes balance with moment of the bond stress around longitudinal bars in the range from the beam end to a distance of beam effective height, which is named the beam end region in this paper. Consequently, the following conclusions were obtained.
 (1) Bond stress around all longitudinal bars in the beam end region decreased once due to cracks. And the bond stress increased again as tensile stress in shear reinforcement increased. In addition, ratio of bond stress in the third layer to the bond stress of all the bars increased by terminating the bars in the third layer.
 (2) In the beam end region, after shear cracking, moment of the bond stress around cut off bars in third layer increased as moment of the tensile stress in shear reinforcement increased until yielding of longitudinal bars.
 (3) When bond stress was calculated in a state that the longitudinal bars almost yielded, tension shift range of d/2, which is a half length of effective beam depth, gave better accuracy than the tension shift range of d, which is required in the AIJ standard.

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 In reinforced concrete (RC) buildings, RC walls are often used as outer walls and inner walls. This wall has the effect of increasing the strength and rigidity of adjacent columns and beams. However, the column/beam to which these walls are attached has complicated shape and arranging reinforcements as compared with a single column beam member, and it is not easy to evaluate strength and rigidity. For this reason, in recent RC buildings, a structure gap is provided between column/beam and adjacent RC walls. It is common to direct designs to behave and design without considering an increase in strength and rigidity by these walls as much as possible.
 It is certain that it is one solution of earthquake-resistant design to frequently use the structural gap and to ensure the required seismic performance by expecting the ductility by bringing the behavior of the building closer to the moment frame. However, in the case of the past earthquake damage, cases where damage was not escaped but expected to be tough, but there were cases where the damage was remarkably damaged, and based on the fact that the strength type building like the so-called wall type structure is less damaged, It is desirable that a design that effectively utilizes the walls and secures the strength and rigidity of buildings to ensure necessary earthquake resistance performance while suppressing damage is also a promising option. For that purpose, no structural gap is provided. Establishment of a simple design method for buildings expected to increase strength and rigidity by RC walls is required.
 In this paper, the author evaluated the ultimate flexural strength of the RC beams with spandrel walls when performing earthquake-resistant design by load-carrying capacity calculation.
 1) In view of the fact that the beams with spandrel walls tend to deteriorate immediately after reaching the maximum flexural strength, it is desirable to secure the required horizontal strength of the building due to the ultimate flexural strength lower than the actual strength. On the other hand, for the shear design and the collapse mechanism guarantee design, an ultimate bending strength formula that can evaluate the upper limit of the actual strength is also desired.
 2) Assuming the compressive stress distribution of concrete to be a triangle distribution, considering the tension force of the compression side beam reinforcement based on the compatibility of the strain, proposed the approximate expression formula for evaluating the lower ultimate flexural strength (equation (5)). It was confirmed that the lower limit of strength can be well evaluated.
 3) Approximate expression formula (equation (6)) for evaluating the upper ultimate flexural strength based on perfect plasticity theory was proposed. In this formula, we confirmed that the upper limit of the actual strength of the beams with spandrel walls can be evaluated roughly by considering the influence of the local compressive strength of the concrete considerably by the constraint of the concrete.

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 In particular, when designing a high-rise building, it is recommended that the entire collapse mechanism (i.e. strong column-weak beam mechanism) be planned and sufficient safety of the building be ensured by allowing earthquake damage to spread throughout the building and by ensuring that the energy generated by the earthquake is absorbed evenly by the entire building. However, it is a matter of serious concern that the damage on every floor causes extensive spreading of the area to be restored, greatly increases the repair cost, and lengthens the restoration period, making functional recovery difficult.
 Developing design methods that consider the safety and post-seismic functionality of buildings is required to reduce damage to buildings and minimize damage to society from major earthquakes. A damage evaluation index which can properly evaluate the severity of the damage from the viewpoint of post-seismic functional recovery is necessary for such design. The authors in this study define the severity of the damage as that which repair time is becoming relatively large. And an “ideal repair time (IRT)”, which is an index that relatively evaluates the severity of the damage, is proposed.
 The IRT has the following features:
 1. Many factors influence the repair time other than the damage state. These factors include the social and surrounding environments, climate, adopted repair methods, work procedures, number of engaged workers, and work proficiency, among others. The repair time would still vary when these factors are different even if the damage state is the same. The IRT is a damage evaluation index that targets only the damage state (i.e., amount, extent, and quality of the damage) by eliminating influences of factors other than the damage state.
 2. From the comparison between the IRT and repair time of damaged buildings in KOBE Earthquake, it was shown that the IRT reasonably evaluates the relative increase in repair time generated by amount and extent of the damage. Furthermore, the validity of quantitative evaluation by IRT was discussed, considering the calculation condition and its influence on repair time.
 3. The IRT evaluates the severity of the damage caused by its amount and extent. Therefore, the influence on the dysfunctional time by each damage in the building can be evaluated, and the damaged areas to be prevented can be identified. The analysis based on the IRT allows structural designers to investigate the validity of the planned collapse mechanism, strength, and stiffness given to the building from the perspective of the post-seismic functional recovery.
 4. The IRT is an index that represents the dysfunctional time caused by the damage. From the IRT, ordinary people with no special knowledge on structural engineering can easily understand the relative difference of the damage severity and the damage-resistant performance given to the building. An index that can indicate the necessity of the damage-resistant performance and the secured level of the performance to the owner of the building is significant.

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 Shear walls in which sheets with burring holes aligned along the vertical direction are fastened to frame members, are applied to multi-story buildings in seismically active regions. A sheet for the standard 2.73-m-high-walls is 2.73-m-long × 0.455-m-wide × 1.0-mm- or 1.2-mm-thickness with seven cold-formed burring holes with the diameter of 200mm, which are created by cold pressing a sheet with small-radius holes. A burring hole contains rib (curvature radius: 10mm and 5mm height cylinder) to make edge-stiffened circular hole. A configuration with burrs on the inside and smooth on the outside enables the construction of omitting the machining of holes for equipment and thinner walls of simplified attachments of finishing.
 In-plane shear experiments and finite element analyses revealed that the walls that receive the in-plane shear force allow shear stress to concentrate in intervals between the burring holes. The walls changed from the elastic to plastic region and maintained stable strength. The walls at 1/300 story angle had stress concentrations at the intervals between the holes. The walls at 1/100 story angle experienced out-of-plane deformation at the all intervals simultaneously. The deformations were limited in the intervals and a large out-of-plane waveform in a sheet was effectively prevented owing to the ring-shaped ribs of the holes.
 Shear stiffness of the wall was gradually decreasing according to the deformation increasing of the wall, even in the elastic region. The burrs of steel sheets on the one side of the sheets created the asymmetry and the directions of principal stress flows on the sheets varied in three dimensions. Therefor out of plane deformations occurred on the sheets and inclined tension fields occurred in the intervals between the burring holes like post shear buckling behavior that Dr. Basler proposed for plate-girder designs.
 In this paper, new design methods are proposed for evaluating the stiffness of the walls using the idea of decreasing the band-width of the inclined tension fields with the effect of the thickness of the steel sheets. The design formula to evaluate the shear strength of the wall at a story angle of 0 to 1/200 was developed and the values obtained using the formula lie almost the same values obtained through experiments.
 The large deformation behavior was also depended on the tension fields on the intervals between the holes. The shear strength at a story angle of 1/200 to 1/100 was increased by the studs restrained by cross-rails. The effect of cross-rails maintained wall strength stable in inelastic region. The tension in an interval between the burring holes was balanced with the compression resisted by a burring-hole and horizontal shear force at screw connections created by studs and a cross-rail. The design formula to evaluate the shear strength of the wall at a story angle of 1/200 to 1/100 was developed and the values obtained using the formula lie almost the same values obtained through experiments.

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 Seismic retrofit has been achieved for the buildings constructed before 1981, and its effects on the improvement to avoid collapse due to an earthquake are reported in the past investigation. Public office, school buildings and gymnasium were retrofitted as priority to secure disaster prevention base in the city. However, it is pointed out that the damaged commercial facility and factory lead to the terrible economic loss in the 2011 Tohoku great earthquake. Although seismic retrofit is needed for factories with lack of seismic performance, the continuous operation causes many temporal and spatial restriction. Especially, retrofit with welding makes the construction impractical because it should pay attention to prevention of fire. Fundamental experimental study on a non-fire strengthening method for bolted angle brace connections were addressed in this paper. In other words, monotonic loading tests were carried out to investigate the effects of the proposed retrofit method. The proposed method in this paper is that the additional member is attached to the existing angle brace by new high strength bolts, the joint bolts. First of all, the ultimate strength for the two expected failure modes was established to select the test parameters. The expected failure mode I is fracture occurred not only at the existing bolt hole but also at the joint hole, and including the diagonal failure line from the existing bolt hole to the joint bolt hole. The failure mode II is fracture occurred at the joint bolt hole only because the joint bolt is located far enough from the existing bolt hole. It indicates that the position of the joint bolt from the existing bolt is an important parameter to determine the failure mode of the retrofit method.
 The test results showed that the additional member increases the ultimate strength of the existing bolted connection. The effects depend on the position of the joint bolt and the ultimate strength increases according to the distance from the existing bolt to the joint bolt, the joint distance x. And although the ductile crack was observed around the 1st existing bolt in specimen with short joint distance, the position of the crack was changed to around the 1st joint bolt in specimen with wide joint distance. It indicates that the failure mode is changed to the failure mode II. The increment of ultimate strength was nearly constant in the failure mode II, and it means that the retrofitted connection is able to reach the maximum strength. Based on the test results with a scatter of material strength on cross section, it is found out that the joint distance has to be 1.5 times or more of the width of the angle cross section in order to change the expected failure mode to mode II, and to maximize the ultimate strength of the bolted connection.

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