Colored concrete is concrete that is colored by the addition of pigment to the concrete mix. Previous studies have shown that the color of colored concrete is influenced by the color of the mortar. To confirm the color values of mortar colored with pigment, the authors have so far reported the change over time of the color values of mortar with different water-binder ratios when using a white base mortar. However, during actual construction, measures to make the color of the base concrete close to white are rarely taken. Thus, in practice, the concrete or mortar that is used as the base of colored concrete is affected by the color of the cement and aggregate commonly used by ready-mixed concrete plants.

　The object of this study is to investigate the effect of the color of binder and fine aggregate on the color values of colored mortar with two different water-binder ratios. The findings were as follows

1)　The material which had an influence on the color of the mortar most was cement. And, the influence of fine aggregate to the color of the mortar was small compared with influence of cement. In the measurement results of white specimen, L* value of mortar decreased about 10 regardless of water-binder ratio when limestone crashed sand was changed to andesite crashed sand. And, L* value of mortar decreased about 30 to 40 when white portland cement was changed to ordinarily portland cement.

2)　It was confirmed that hardened cement using ordinarily portland cement can't be colored effectively compared with hardened cement using white portland cement. The effect of coloring to mortar using ordinarily portland cement was different depending on the color of the pigment. When using blue pigment for mortar using ordinarily portland cement, the mortar which can be manufactured will be the color near the gray. As this reason, ordinarily portland cement may include complementary color element against blue pigment.

3)　The brightness of mortar with water binder ratio 0.2 fell about 10 % compare with mortar with water binder ratio 0.5.

　In current Recommendations for Loads on Buildings (Architectural Institute of Japan, 2015) (abbreviated as AIJ-RLB (2015)), wind loads are determined based on the concept of an equivalent static wind load, and structural frames are assumed to behave elastically in strong wind. The along-wind load is generally composed of a mean component caused by the mean wind speed, a quasi-static component caused by relatively low frequency fluctuation and the 1st mode resonant component caused by fluctuation in the vicinity of the natural frequency. In AIJ-RLB (2015), the procedure that can estimate the equivalent static wind load producing the maximum structural responses using the gust effect factor was prescribed. For along-wind load, various force coefficients (in AIJ-RLB (2015), wind force coefficient at the top of the building, a factor relevant to overturning moment in the along-wind direction and a factor relevant to rms overturning moment in the along-wind direction), which were used to calculate the mean load and gust effect factor, were modeled as a functions of building shapes and approaching flow characteristics. The across-wind load can be obtained by multiplying fluctuating overturning moment coefficients by the peak factor and the fluctuating overturning moment coefficients were modeled as a function of side ratio only.

　The wind force coefficients in AIJ-RLB (2015) are prescribed based on the wind tunnel tests as an ensemble average of ten and/or twenty 10-minute samples. The small number of 10-minute samples makes it difficult, almost impossible, to identify the exact probability distribution and exceedance probability of the prescribed force coefficients.

　In the present study, more than 10,000 10-munute samples on tall buildings were measured by wind tunnel tests, and the probability distributions of local force and overturning moment coefficients, which were used for the evaluation of the horizontal wind loads on structural frame, were identified first and the design local force and overturning moment coefficients corresponding to the specific non-exceedance probabilities of wind load were calculated based on the probabilistic theory.

　The following concluding remarks can be made from the calculation results.

1) It was possible to identify the probability distributions and non-exceedance probabilities of various wind force coefficients prescribed in AIJ-RLB (2015).

2) The coefficient of variance of wind force coefficients depends on the force components, generally showing larger coefficient of variance assumed in AIJ-RLB (2015).

3) The probability distributions of all the mean and fluctuating force coefficients were found to be normal distribution. And the ratio of the design force coefficient to the arithmetic mean of 10-minutes samples was less than 2%.

4) Considering the arithmetic mean of 10-minute samples corresponds to the value in the AIJ-RLB (2015), the non-exceedance probability of the force coefficients prescribed in AIJ-RLB (2015) could be interpreted to be similar to 99.9%.

　In Japan, the ‘Recipe’ compiled by the Headquarters for Earthquake Research Promotion, Japan, has been often adopted for estimating fault parameters to predict strong earthquake motions, and applied to many practices. However, it does not model the shallow part of the fault of the ruptured area because Dalguer et al. (2001) showed by the dynamic fault rupturing simulations that the fault rupturing reaches the ground surface as fault dislocations after the rupturing of the basement rock, which radiates seismic energy, propagates in the sedimentary rock from the depth of a few kilometers to the ground surface even if the sedimentary rock has little or no stress drop. Hence, the ‘Recipe’ can not predict permanent displacements in the area very close to the fault trace.

　On the other hand, the 2016 Kumamoto, Japan, earthquake provided precious data of strong motions including the permanent displacements, and these permanent displacements caused severe damage to structures. Since then, several research teams have conducted studies to reproduce and predict these strong motions including permanent displacements.

　I reviewed these studies, categorizing them into three groups: reproducing strong motions by kinematic source model, extending the ‘Recipe’ in order to model the shallow part of the ruptured area, and reproducing permanent displacement by empirical model. I finally proposed two procedures for modeling the second- and third-stage earthquakes, which have surface fault breakings such as the Kumamoto earthquake, to predict strong motions including permanent displacements in the areas very close to the fault trace on the ground surface.

　Recently, with the progress of research on earthquake ground motion, it has become necessary to increase the out-of-plane shear force used in the design of reinforced concrete flat plates such as foundation slabs and underground outer walls. There is a concern that out-of-plane shear failure occurs in these flat plates of existing buildings with insufficient amount of shear reinforcement during coming severe earthquake. However, effective seismic retrofitting of foundation slabs or underground outer walls is difficult because the construction work can be completed only from the inside of building. To address this problem, a post-installed shear reinforcement (PSR) method was developed.

　The PSR consists of a deformed bar and ceramic or steel anchorages, called “ceramic cap bar (CCb)” or “steel cap bar (SCb)”, respectively, at both ends of the bar. In this method, after drilling holes in the existing foundation slabs or the underground outer walls, PSR is inserted into the hole from the inner space of the building, and finally grout is injected to integrate the PSR with the structure.

　In order to grasp the out-of-plane shear characteristics of a flat plate reinforced with PSR and to develop a formula to predict its shear strength, 31 test specimens were experimented. The main parameters were the presence or absence of PSR, the material of the anchorage, the length and amount of PSR, the shear span ratio and the size of the specimen.

　The major findings from this study are as follows:

1)　In the member with PSR, shear cracks progressed and widened in the hinge region where the area around the tip of PSR is near the bending tension side. The cracks then developed in the horizontal direction so as to connect the PSR tip and reached the maximum strength. After the maximum strength, these horizontal cracks developed and widened, and the damage progressed.

2)　Based on Arakawa’s formula, a formula to predict the out-of-plane shear strength of the flat plate seismically retrofitted with PSR was proposed. This formula includes the “shear reinforcement effectiveness ratio”, which accounts for strength development characteristics of PSR, and the “effective section ratio”, which indicates that the outer concrete from the tip of PSR does not contribute to the shear resistance. With this formula, the out-of-plane shear strength was predicted on the safe side.

　Recently, various studies have been conducted to prevent joint hinging failure of reinforced concrete beam-column joints. In particular, there are many experimental studies related to hinge relocation method. However, most of these are tested by interior and exterior beam-column joint subassemblages specimens, few experimental studies with only beam members have been carried out.

　In this study, flexure and shear tests were conducted to clarify the structural performance of reinforced concrete beam with plastic hinge relocation method, to further improve the seismic performance and to ensure quality and productivity in the construction of high-rise RC buildings. Specimens were ten 1/2-scale reinforced concrete beams with relocating plastic hinge region at the both ends of beam. The main test parameters were shape of cross section (T-shape half precast, rectangular), method of relocating plastic hinge away from the stub face (connecting main reinforcement at the beam ends having different diameters or different strength using mechanical splices, cut-off of main reinforcement using anchorages), distance from the stub face of relocated critical section, shear span ratio, and amount of transverse reinforcement.

　As a result of the tests, it was found that crack patterns, failure modes, load-deformation relationship and plastic deformation capacity were affected according to the parameter. This paper studies the strain and stress distribution of longitudinal bar, deformation component of the member, evaluation method of restoring force characteristics and failure mode for use in practical design. The analysis and discussion of test results lead to the following conclusion:

(1)　The characteristic and position of relocated plastic hinge of beam can be controlled as designed by the two methods considered in this study.

(2)　The restoring force characteristics can be evaluated taking into consideration the effect of the relocation of critical section by using evaluation formulas currently in use.

(3)　The failure mode can be estimated by comparing the shear margin and the bond stress margin. Provided that both of these are greater than 1.0 brittle failure can be prevented after flexural yielding.

To strengthen reinforced concrete structures against seismic events, design methods are being established to fit the interiors of existing structures with steel braces or shear walls and to retrofit existing structures with steel braces on the exterior of existing frames for seismic protection. For example, indirect connections that use post-installed anchors are frequently employed in steel-braced frames for seismic retrofits, and many post-installed anchors are required for each existing structure. The connection between the existing structures and reinforcement elements in the seismic retrofitting of concrete construction must be effective in distributing stress. If the strength of the connection is not adequate and if the details are not properly designed, the structure as a whole is not likely to display effective seismic performance. Therefore, we proposed a new method that uses shear connecters with a steel shear key in a frustoconical shape and post-installed anchors for connecting existing concrete to extended concrete. We call this shear connecter the “funnel-shaped post-installed anchor.” In a former study, experiments and non-linear finite element method analysis on the strengthening method that used funnel-shaped post-installed anchors reported that funnel-shaped post-installed anchors with a 45-degree shear key improved shear strength compared with keys with other shapes. However, no shear strength formula has been established for this new type of shear connecter.

In this paper, based on the mechanisms of resistance and failure mode, we propose the shear strength formula for a shear connecter with a steel shear key having frustoconical shape and a post-installed anchor. This formula assumes tensile failure in the post-installed anchor and bearing failure in the concrete around the shear key. To confirm the accuracy of the proposed analysis model and equation, we investigated the failure mode and the shear strength of the shear connecter using structural tests under a cyclic shear force. The outside diameter of the shear key (50 mm or 70 mm), shape of the surface of the shear key (irregular or flat), material of the anchor bar (SS400 or SNB7), anchorage length of the anchor bar in existing concrete (12d_a or 7d_a), and strength of existing concrete (F_c15, F_c24, or F_c33) were used as experimental parameters. The experiments confirm that the effects on shear strength corresponded to the results of the experiment and calculation model.

Finally, we proposed a method for evaluating shear strength by considering the mechanical behavior of a rotating shear key in experiments. The calculated shear strength was consistent with the experimental values.

　This study proposes a damage mitigation technique of reinforced concrete buildings using high-performance fiber-reinforced cementitious composites (HPFRCC) secondary walls. It verified functional continuity after big earthquakes by the static loading test and the seismic response analyses. This technique reduces damages to the buildings by utilizing the HPFRCC secondary walls

　In the static loading test, a full-scale specimen that had a 1-story 1-span plane frame with the precast HPFRCC secondary walls was used based on a small-scale specimen of the previous research. The span length is 5,000 mm with a story height of 2,750 mm. The section of the column is 600 mm × 600 mm. The HPFRCC secondary wall has the thickness of 100 mm, a door-shaped opening of 2,000 mm × 900 mm and a window-shaped opening of 900 mm × 900 mm. In the loading method, a vertical force with an axial force ratio of 0.1 was applied to the column cores on both sides, and an incremental cyclic force was applied to the loading stub at the top of the specimen. From a viewpoint of post-earthquake functionality, a relationship between damage and deformation was examined. As a result, it was found that if a story drift angle is 1/200 rad or less, damage to the secondary walls and the RC frames is relatively minor, and continuous usability after big earthquakes can be ensured.

　In the seismic response analyses, hysteresis characteristics obtained in a full-scale test were approximated by the Takeda model, and the response characteristics of the 5-story RC model building with the HPFRCC secondary walls to the notification waves (random phase, JMA Kobe phase, Hachinohe phase) were examined. The results showed that the maximum drift angle was 1/200 rad or less for the seismic waves using the Kobe phase and the Hachinohe phase, while it slightly exceeded 1/200 rad for the seismic waves using the random phase. However, it is presumed that a response value can be reduced by making a secondary wall a little thicker to increase structural stiffness.

　In arch model, stresses in longitudinal steels are supposed to be constant along the length of the steels, and hence to investigating the shear transfer mechanism of the arch model, concrete members having unbonded longitudinal steels have been tested. Consequently, the arch model has been applied to the prediction of ultimate shear strength of precast concrete members assembled by tendons.

　This paper analyzes test results in past investigations on mechanical behavior of members having unbonded

longitudinal steels, and it is found that:

1) The modes of failure are classified flexural compression failure and diagonal tension failure.

2) The distributions of concrete compressive strain are consistent with the assumption of plane sections remains plane, and those corresponding to the diagonal strut in the arch mechanism are not found, in the members that fail in the diagonal tension as well as those that fail in flexural compression.

3) Under the same amount of longitudinal reinforcement and concrete compressive strength, the ultimate bending moment of the test beams are the same whether their modes of failure are flexural compression or diagonal tension.

　These findings provide the evidence that the mechanical behaviors of the members having unbonded longitudinal

steels are governed by flexural theory, and their ultimate strength should be expressed by ultimate bending moment.

　Based on the evidence mentioned above, equations using a lower bound theory of plasticity are proposed for predicting ultimate bending moment of the precast members assembled by unbonded tendons. Comparisons are made between the measured, Meu and estimated, Mu ultimate bending moment using data from 64 test specimens with unbonded longitudinal steels. Forty two out of the 64 test specimens fail in the flexural compression and remaining specimens fail in diagonal tension. The average of Meu / Mu and the coefficient of variation are 1.016 and 7.56%, respectively and the probability that Meu / Mu > 1.2 or Meu / Mu < 0.8 is 0% with respect to the 64 specimens. The average and coefficient of variation with respect to the specimens that fail in flexural compression are 1.024 and 7.71%, and those for the specimens that fail in diagonal tension are 1.00 and 6.91%. These statistical results show that

1) The proposed equations have high accuracy.

2) The average and the coefficient of variation do not depend on the modes of failure.

　At the moment-resisting frame systems, the external horizontal forces are subjected to the structure will be resisted by the columns' flexural manners. Therefore, the columns are under compressive axial force with bending moment (i.e., combined loading conditions). Moreover, the columns will be subjected to cyclic bending at the seismic event. The ultimate state of square steel tubular column, which has a closed cross-section, will be governed by local buckling or Pδ moment. On the other hand, the ultimate state of H-shaped column, which has an open cross-section, will be governed by either lateral-torsional buckling, local buckling, or Pδ moment. The H-shaped columns' design formulas are specified in the "Recommendation for Plastic Design of Steel structures (PD Recommendation)" published by AIJ. However, due to the limited number of test results gathered in the 1980s, the application range is not clarified.

　In this study, steel column testing under combined loading conditions was conducted to verify the relatively deep H-shaped cross-sectionsʼ structural performances. The cyclic bending moment was applied to the specimens; deformed shape, strength, and deformation capacity were evaluated as the structural performances. The selected parameters for the specimen are axial compressive force, member length, and the shape of cross-section. Two types of cross-section were selected, one is H-150×75×5×7 (Deep wide-flange column), and the other is H-148×100×6×9 (Middle wide-flange column).

　From this study, the following results were found:

1)　The ultimate state of most specimens was governed by lateral-torsional buckling behavior. Out-of-plane deformation due to the lateral-torsional buckling occurred at the middle of the member when the column was slender, and the axial force was high. Deep wide-flange columns where the length is equal to 1700mm were governed by local buckling that appeared at the member end after observing some amount of lateral-torsional behavior in the member.

2)　The specimens which fulfilled the requirements of PD Recommendation showed adequate performance when the column was middle wide-flange. On the other hand, when the column was deep wide-flange, some specimens showed unconservative performances.

3)　In order to clarify the plastic deformation capacity in the loading direction, the following Indexes were evaluated; Maximum plastic deformation capacity _cθ_pmax, the cumulative plastic deformation capacity Σ_cθ_pl, the plastic deformation capacity R. Even though some specimens fulfilled the requirements to form a plastic hinge (Eq. (2) ~ (5), Eq. (8) ~ (9)), the value given in PD Recommendation could not be reached. Plastic deformation capacity, especially cumulative plastic deformation capacity Σ_cθ_pl, are assumed to be susceptible to lateral-torsional buckling.

4)　Some specimens could be appropriately evaluated by Ref. 10); however, others could not be evaluated due to the application range's limitation. Besides, almost all specimens could not be appropriately evaluated by Ref. 14) and Ref. 5). This result was due to the evaluation index; the sensitivity of lateral-torsional buckling was not included in it.

　In conclusion, the degradation of the H-shaped columns' structural performance (especially, deep wide-flange column) due to lateral-torsional buckling must be evaluated adequately. In order to compose the design formulas for H-shaped columns, a consideration of the index that includes the sensitivity of lateral-torsional buckling is needed. This issue will be a future topic.

　　The low-rise steel-framed buildings that make up a large space are expected to function as disaster prevention bases in the event of a disaster due to their high capacity and are required to ensure high seismic performance in order to demonstrate their functions as bases. H-shaped members are often used for columns in such a structure, and brace members generally connect the weak axis direction. The brace members that resist seismic load are essential structural members, and its connection strength has a significant influence on the frame's behavior and strength, including the brace members, so it does not break at the joint until the member is yielded. Currently, strength formulae for braced members constructed based on experimental results on specimens with a plate thickness of 6.0 mm or more are used. However, in recent steel structural buildings, thin members are used as structural members in order to improve the efficiency and weight of the cross-section of the members. Based on the above, in this paper, the shape factors that affect the joint strength of the braced members composed of thin plates (thickness of 6.0 mm or less) are clarified by joint tensile experiments and finite element numerical analysis. The purpose of this study is to propose unified evaluation formulae for bolted connection members, which can apply to the members composed from thin plate members to thick plate members.

　　From this research，the following are found．

1)　From experimental and numerical analysis results, plate thickness, outstanding leg length, and cross-sectional shape affect joint efficiency. These parameters are shape variables related to the eccentric distance of the connection, and the joint efficiency decreased as the increment of the eccentric distance.

2)　The strength of the connection is hardly affected by the thickness of the gusset plate and the length of the member.

3)　Even if the number of bolts and the bolt pitch are different, if the joint length is the same, the strength of the connection is the same, and the joint efficiency increase as the joint length increases.

4)　The strength formulas in Japan and overseas can conservatively evaluate the ultimate strength of the brace members in a relatively small range up to a width-thickness ratio of about 20 or less. On the other hand, thin plate members with a width-thickness ratio greater than 20 tend to be overestimated.

5)　The ultimate strength evaluation formula is proposed using the combination variable of the eccentric distance of the cross-section and the joint length, and the ratio of the bolt hole diameter and the joint leg width. The proposed evaluation formula gives a reasonable evaluation to the brace members, which occur net section fracture, from thin plates to thick plates, and is more significant than the existing strength formulas. Also, a strength formula for yield strength is proposed. And the validity of the formula is shown by comparing it with the experimental results.