Abstract:In this chapter, the fire resistance of reinforced concrete and prestressed concrete structures are outlined to expend further research. The progress and prospect in fire resistance of reinforced concrete (RC) structures and prestressed concrete (PC) structures and its repair technology after fire is presented, and some issues that still need to be investigated are discussed. The progress mainly includes mechanical properties of materials at elevated temperatures, fire resistance of RC and PC structures, and fire-induced spalling of concrete. The results show that spalling critical temperature of concrete varies with compressive strength of concrete. Adding steel fibers or polypropylene (PP) fibers is able to prevent fire-included spalling of concrete effectively. The criteria considering nominal stress of concrete and concrete strength is effective for judging fire-induced spalling, which is capable for reducing the possibility of fire-induced spalling of concrete in PC members. The requirements that concrete structures will not collapse or spalling during fire and can be repaired after fire should be satisfied in fire safety design. Rational fibers dosage to prevent fire-included spalling of concrete, fire-included spalling and its prediction model on RC and PC members, fire-induced spalling of RPC, temperature-stress coupling strain-stress relation of RPC and fire resistance of RPC members, effect of force-temperature paths on behaviors of structures and members, fire resistance of high-rise buildings and underground structures are the main problems which need to be studied in the future.

Abstract:To study the seismic behavior of assembled monolithic beam-column joints, quasi-static tests of one precast exterior joint PEJ1 with the shear failure of joint core area and one precast exterior joint PEJ2 with the flexural failure of beam fixed end were carried out. For the specimen PEJ1, core area hoops yield first and the core concrete fails in shear mode obviously. For the specimen PEJ2, concrete of beam fixed end crushes and beam longitudinal rebars yield while core area hoops don′t yield. The two specimens both fail in the expected failure modes. The hysteretic loops of the two specimens have a certain extent of pinch while the specimen PEJ1 shows a slightly larger extent of pinch. The skeleton curve of the specimen PEJ1 declines rapidly after peak load. The measured load-carrying capacity of the precast joints, which fail in shear mode in the joint core area and flexural mode at the beam fixed end, respectively are 1.30, 1.26 times as large as the calculated capacity according to the formulas in the current design code. The equivalent ultimate drift ratios of the two specimens are 1/28 and 1/22. The specimen PEJ1 is dominated by deformation of the beam at the peak point and shear deformation of the core area at the ultimate point. The specimen PEJ2 is dominated by deformation of the beam during the whole experiment while the contribution of shear deformation of the core area is less than 5%. The anchor failure of the beam longitudinal rebars does not occur. In the precast exterior joints with different failure modes, utilizing heads to anchor beam longitudinal rebars is feasible.

Abstract:To study the erosion degradation rule of the concrete member under different chloride ion erosion conditions, the chloride ion immersion tests for the flexural-tensile concrete member and salt spray tests for non-stress concrete member were carried out. Based on the test results of chloride mass fraction, flexural-tensile strength and flexural-tensile strain of concrete member, the effects of erosion time, environmental temperature, stress level, environmental chloride ion mass fraction and erosion pattern on the diffusion rule of chloride ion and flexural-tensile strength of concrete members were studied. The results show that, the chloride ion mass fraction in soaking environment is higher than that in salt spray environment; the chloride ion mass fraction increases with the erosion time, environmental temperature, chloride ion concentration and stress level; the diffusion coefficient increases with the increasing of the stress level and temperature; under the condition of lower stress level, lower temperature and shorter erosion time, the ultimate flexural-tensile strength of concrete members has a slight upward trend, and then it decreases with erosion time; the ultimate flexural-tensile strain of concrete members decreases while the influence factors increase. The results provide a theoretical base for the durability assessment and design for concrete member under chloride ion erosion environmental and have some practical values.

Abstract:To improve the construction convenience of grouted splice connector, grouted sleeve lapping connector with independent intellectual property rights was put forward. A total of 63 specimens varied in bar diameter and lap length were tested under tensile load to study the mechanical properties of grouted sleeve lapping connector, which provides important scientific data for the application of the connector in precast concrete components. Failure modes, ultimate tensile capabilities, load-displacement curves and reinforcement and sleeve strains of the specimens were discussed. Bar fracture and bar-grout bond slip are the typical failure modes of the specimens, grout-sleeve bond failure and sleeve tensile fracture do not appear. Compared with the steel bar, the ultimate tensile capacity and the load-displacement curve of the connector are similar, while the stiffness is a bit lower. For specimens with the same bar diameter that failed by bar fracture, transverse confinement provided by the sleeve wall decreases as lap length increases. For specimens with bar-grout bond failure, bar diameter increase leads to an increase in confinement stress generated by the sleeve wall. The working mechanisms of grouted sleeve lapping connector and butting connector were analyzed. Compared with grouted sleeve lapping connector, sleeves with stronger tensile capacity and grout-sleeve with higher bond performance are needed to guarantee the working performance of grouted sleeve butting connector. The mechanical properties and mechanical model of grouted sleeve lapping connector were analyzed. Two equations were proposed to calculate the average lapping bond stress and critical lap length. Under confinement, the required lap length can be shortened greatly. The recommended lap length is 12.5 times bar diameter.

Abstract:To prevent reinforced concrete (RC) frame columns from seismic shear failure caused by additional shear force of the infill wall, severe shear failures of RC frame columns investigated in recent earthquakes were presented. Finite element modeling (FEM) pushover analysis with ABAQUS and mechanical characteristics analysis on 6 infilled RC frames were conducted. Then a RC frame structure subjected to LuDian Ms6.5 earthquake was analyzed by ABAQUS. The analysis indicates that the additional shear force of the infill wall results in the shear failure of the column. To ensure that a structure operates in a high-ductility mode, an estimation formula was developed for the additional shear force which could be used in structure design. The case study shows that without appropriate considerations about the additional shear force of the infill wall, anti-collapse capability of the structure will be threatened seriously. Analysis also demonstrates that the additional shear force estimation formula is in well accordance with the FEM analysis result and the seismic damage investigations, it can be a reference for engineering design.

Abstract:To assess the durability status and remaining service life of existing concrete dock located at Beibu Gulf, the propagation phase was evaluated based on the in situ test data and concrete cover corrosion-crack model. The results indicate that the propagation phase will last about 2.09-22.77 years based on eight deterministic models. The empirical values of 2-5 years, recommended by scholars and engineers, would be more reasonable when the RC structures were exposed to harsh corrosion environment. According to the probabilistic model, the uncertainty of limit crack width and time-dependent characteristic of the corrosion rate were taken into considered, the propagation phase equated to 12.7 years, which was fitted with the deterministic models. The limit crack width and corrosion rate significantly affect the assessment of the propagation phase. When the value of corrosion rate increases from 0.5 to 1.0 μA/cm², the value of the propagation phase decreases by 14.75 %; and the value of the propagation phase increases by 39.13 % when the value of limit crack width rises from 0.15 to 0.50 mm. The study shows that the tested concrete dock can meet the requirement of design service life.

Abstract:To investigate the shear lag effect of thin-walled box girder on the dynamic characteristics, a new approach was developed to analyze the free vibration of box girders based on the modal perturbation method. The natural modes of vibration of the corresponding prismatic Euler beam with the same length and boundary conditions were used as Ritz base functions. Then, the new method can transform the set of partial differential equations governing the transverse vibration of the box girder into a set of nonlinear algebraic equations. For the simply-supported beams, the algebraic equations were further simplified as quadratic equation with one unknown, so that the exact eigenvalues and eigenvectors could be obtained. The analytical vibration modes of the box girder were used to propose the shear lag coefficients of modes, which illustrates the relationship between the natural frequency and shear lag effect. Numerical examples were used to analyze the shear lag coefficients of modes varying with the ratio between span and width, the second moment of area ratio between flange slab and the full section. The numerical results show that the maximum shear lag coefficients of modes located at the web of the box girder are greater than 1, which are positive shear lag effect. As the increase of modes order, the reduction of the ratio between span and width and the increase of the second moment of area ratio between flange slab and the full section, the shear lag coefficients and shear lag effect would be more remarkable.

Abstract:The threaded-sleeve connection (TSC) is a new type of connection for grid structure, of which the key part situates at the threaded extended end. The simulation models of TSC were established and compared by ANSYS. The compression mechanical property and stress distribution were analyzed firstly. The performance of compression and eccentric compression were tested through experiments. The simulation results were compared with test data to verify the correctness of the FE model. Based on the simulation and experimental results, the theoretical formulas of compression capacity and stiffness of the extended end were developed. It is illustrated that the capacity of TSC under compression is about 63.2% of that of the pipe with same material, diameter and wall thickness. When subjected to large eccentricity, the capacity of TSC decreases to about 83.9% of the axial compressive capacity. The failure form of the specimens under compression or eccentric compression is the buckling of the extended threads. The simulation results agree well with the test results, which illustrates the effectiveness of the FE method, and the theoretical results are also in good agreement with the test data. The TSC shares good compression performance, and the most weakness area exists in the extended part of the threads, the buckling of which will lead to the failure of the connection.

Abstract:Pitting corrosion is a local and severe form of corrosion, resulting in degradation of the mechanical properties for structural members and security risks for the whole structures caused by sudden accident. A simplified analytical method for the quantitative evaluation of the mechanical properties of steel members with pitting corrosion resistance was proposed by equivalent elastic modulus. Based on experimental data, an analytical method was proposed to calculate the mechanical properties of members with pitting corrosion. In this method, some assumptions about the pitting depth, diameter and distribution were put forward. Considering the influence of the coating life, the relationship of corrosion status between in laboratory and in ocean atmosphere was established according to the same corrosion rate. Based on axial compression FEM model, the equivalent elastic modulus of structural members with pitting corrosion was obtained. Through curve fitting, practical method was proposed to obtain the mechanical properties of members in ocean atmosphere. A numerical example demonstrated the validity of the proposed method using equivalent elastic modulus to analyze the mechanical properties of pitting corrosion members. The calculated results indicate that, with the same corrosion rate, the equivalent elastic modulus of pitting corrosion members is lower than that of uniform corrosion members.

Abstract:To analyze the influence of explosion-proof wall on antiknock performance for large-span reticulated shell structures, propagation of blast shock waves around explosion-proof wall was simulated with finite element software ANSYS/LS-DYNA. The ALE (Arbitrary-Lagrange-Euler) algorithm was determined due to good agreement with experiment. A kiewitt8 single-layer reticulated shell of refinement was established to simulate the dynamic responses of structure considering explosion-proof wall subjected to external blast loading. The response rules of the structure with varied height, position of explosion-proof wall and span ratio of reticulated shell were obtained to analyze the effects of explosion-proof wall and structure on circulating and reflecting action of blast shock wave. Dangerous height of explosion-proof wall including specific values was proposed, which could provide reference for reasonable defense design of reticulated shell structure.

Abstract:To study the mechanical properties of steel and concrete composite joints under axial compression loads, ten steel and concrete composite joints with different parameters were tested. The main parameter changes of test member include: an inner pipe wall thickness and the radius of the circle, the wall thickness of the outer pipe and the connections between rectangular steel tube and the outer tubes. The experimental results show that steel and concrete composite joints have much in common with steel and concrete, i.e., it has high capacity and good plastic deformation capacity under axial compression loads; the wall thickness and radius of inner pipe is larger than the wall thickness of the outer pipe on the bearing capacity. Connections have greater influence on the joints bearing capacity than others. The bearing capacity of round steel tube is higher than rectangular one and it will be raised at least 15% than the same capacity of round steel tubes and rectangular ones. Under axial compression loads, the failure mode of joints can be divided into central compression failure and spindle deflection failure. Under eccentric loading, the failure mode of joints is divided into joints failure and steel yield damage of pipe.

Abstract:Considering the initial and induced anisotropy of the soil, the solutions to the stress and pore water pressure around a jacked pile, based on K₀ modified Cam-clay model (K₀-MCC), were derived by using cylindrical cavity expansion to simulate the pile installation. Meanwhile, with the axial consolidation theory and the elastic-plane hypothesis for the reconsolidation of the soil around the jacked pile, governing equation for consolidation was established. The variation of the soil strength with reconsolidation time was studied with relaxation effect based on the above studies, and the theoretical solution was then verified by the centrifuge model tests. The results show that the presented theoretical method can properly predict the time-dependent soil strength and the change of excess pore water stress after the pile installation, and the over-consolidation ratio, static lateral pressure coefficient and effective angle of internal friction of soil also have influence on the time-dependent soil strength around the pile. The solution of time-dependent strength of soil can provide theoretical basis for the prediction of time-depended bearing capacity of jacked pile in saturated clay.

Abstract:To study the corner effect of the earth pressure for small-sized excavation, the spatial distribution of active earth pressure was studied for excavations with different sizes, using laboratory model test and the FLAC^3d respectively. The influences of L/H (L is the length of primary wall; H is the excavation depth) and L/B (B is the length of complementary wall) on the significance of corner effect were also analyzed. The results show that: the distribution of active soil pressure displays the effect of corners in the depth of 1.5H; the distance affected by the corner effect is almost the same (within 0.2H from the corner) for different sizes of excavations; the shear stress in cement-stabilised soil is greater on the corner section because of the existence of the corner effect; for relatively small L/H, the significance of corner effect is mainly affected by L/H; the significance of corner effect seems to be independent of L/B.

Abstract:To evaluate the sand consolidation effect of MICP under the condition of the laboratory, the stiffness and permeability of the liquefied sand samples of different size under different grouting flow velocity were analyzed by monitoring the change of internal pressure and the amount of ammonium ion in the process of the grouting of nutrient salt. Sporosarcina pasteurii was selected to produce bacteria liquid, with nutritive salts, such as calcium acetate and urea. The intermittent grouting method was applied to produce solidified sand samples. Results show that the MICP modification effect can be effectively characterized with the variation of internal pressure and the concentration of ammonium during grouting. When grouting velocity is designed according to the area ratio, the grouting pressure is significantly lower down and mineralization uniformity is significantly improved along with the sample size increasing. Monitoring the change of the pressure and the amount of ammonium ion is a simple and non-destructive method for the study of the effect of the microbial treatment of liquefied sand soil. In the application of MICP, the design of grouting should consider both rigidity and mineralization uniformity when the sample size is enlarged.

Abstract:To investigate the relaxation characteristic of rock mass discontinuity with different slope ratios and normal stresses, the stress relaxation tests of dentate discontinuity poured by cement mortar on the condition of shear stress were carried out by using biaxial creep machine. The test results show that: the relaxation curves can be divided into three stages, i.e. the instantaneous relaxation stage, attenuation relaxation stage and stable relaxation stage; the shear nonlinear Maxwell relaxation equation is obtained by constructing the relation between viscosity coefficient and time, the curves of the empirical equation agree with the test ones and get change law of initial viscosity coefficient and change rate with shear stress; according to change law of relaxation stress with shear stress and mechanism of determining long-term strength using transition creep law, a stress relaxation method is proposed to determine the long-term strength, which is relaxation stress peak method.

Abstract:To study mechanical properties of frozen soil under complex stress path, a novel frozen soil testing system-Frozen Hollow Cylinder Apparatus-300(FHCA-300) was developed by State Key Laboratory of Frozen Soils Engineering and the GCTS company in America. By independently controlling inner, outer confine pressure, axial load and torque, this apparatus can change the magnitude and direction of three principal stresses to accurately simulate the stress-strain behavior of frozen soil under complex stress path including the principal stress rotation and multriaxial stress induced by traffic or seismic. This paper introduced the components of FHCA-300, the selection process of sensors, the frequency of dynamic load and the concrete experimental types in details. The design principle of the temperature control system was concretely presented, and the temperature control ability was verified as well. The results show that the system can meet the desired temperature control requirements. For investigating the apparatus' performance of realizing the complex stress path including principal stress rotation, static principal stress axis rotation and cyclic rotation tests were designed, preliminary test results show that the instrument can accurately reproduce the frozen soil mechanical and deformation behaviors in complex stress path condition. It provides technical means for systematical researches on the strength, deformation characteristics and constitutive relation of frozen soil under complex stress condition.

Abstract:To investigate the Swelling-Shrinking characteristics and irreversible deformation of expansive soil under different pressures and moisture contents, a series of tests under wetting-drying cycles were carried out, and the Swelling-Shrinking characteristics and reasons for fissuring were analyzed from the microcosmic point of view. Based on the above studies, the relationship among heights, relative expansion ratios, relative linear shrinking rates and cycle index under different pressures and moisture contents were explored. Meanwhile, the variation curves of the relative irreversible deformation and accumulative irreversible deformation with increasing cycle index were obtained. The results indicate that the swelling and shrinking are visualized response of the variation of water between soil particles, and also the incentive of fissuring. During the shrinking process, the matric suction increases by the way of maximum limit to prevent moisture content decreasing. There is a linear correlation between the height of test specimen and moisture content under different pressures. The relative expansion ratios will decrease if the cycle index rises, and the same happens with higher pressure. The relative linear shrinking rates will rises firstly and then decreases with the increasing of cycle index. It is shown that the relative expansion ratios and relative linear shrinking rates under different amplitudes of moisture content have a decreasing trend along with the increase of cycle index. The accumulative irreversible deformations increase gradually on the condition that the moisture content is 15% with different pressures, and there will be opposite results with the moisture content of 25%.

Abstract:To investigate the feasibility of geopolymer mortar as a repair material for strengthening concrete structures in which fire resistance is one of the primary requirements, tensile strength and bond strength of geopolymer mortar on Portland cement mortar and concrete substrate were tested at ambient temperature and after exposure to elevated temperatures. Comparative tests were conducted on cement mortar specimens. Thermogravimetry and differential scanning calorimetry (TG-DSC) analysis were conducted on geopolymer paste to explore the strength degradation mechanism of geopolymer mortar at high temperatures. The results show that the bond strength of geopolymer mortar at ambient temperature on cement mortar and cement concrete substrate is 2.15 MPa and 1.7 MPa respectively, and the residual bond strength is about 1.5 MPa after exposure to 300 ℃, which is much higher than that of Portland cement mortar. When temperatures exceed 300 ℃, geopolymer mortar exhibits significant strength degradation, due to the microstructural damage induced by the dehydration of geopolymers at high temperatures. Based on the above test results, geopolymer mortar can be used as a repair material for concrete structures in high temperature environment below 300 ℃.

Abstract:To understand the rate-dependent mechanical properties and failure mechanism, a series of uniaxial off-axial tensile tests were carried out to study the mechanical properties of three common PTFE (Poly tetra fluoro ethylene) coated fabrics under different tensile rates. The following parameters were considered in the tests including eleven in-plane directions (0°, 5°, 15°, 25°, 35°, 45°, 55°, 65°, 75°, 85°and 90°) and six tensile rates (10 mm/min, 25 mm/min, 50 mm/min, 100 mm/min, 200 mm/min, and 500 mm/min). The variations of main mechanical parameters of PTFE coated fabrics were analyzed and the corresponding tensile failure modes and mechanisms were studied. The results show that the variations of main mechanical parameters are consistent under different tensile rates and it shows significant anisotropic characteristic. The tensile strength is strongly related with the failure modes. With tensile rate increasing, the tensile strength increases slightly while the strain at break decreases. The tensile strength shows good linear relationship with the tensile rate's logarithm, which is mainly related with the strain energy and the woven structure. The change of tensile rate has no significant effects on the material failure modes and the strain at break.

Abstract:To accurately describe the geometrical characteristic of shrinkage crack and determine the influence on chloride ion permeability in concrete, by taking samples of shrinkage cracking concrete slab and observing the morphology, the characteristics of shrinkage cracks was statistically analyzed, and the effect law of cracks on chloride ion permeability, tested with ASTM method, was studied. The experimental result shows that the depth and width of shrinkage cracks in concrete are obviously related, which the depth-to-width ratio is 44.31, and the crack tip angle is 2.6 by average. Based on the comparative analysis of the relationship between width parameters e.g. maximum width, minimum width, average width, specific surface area etc. and 6 h electric flux, the maximum width is a suitable parameter for describing the effect of shrinkage crack on permeability of concrete. The permeability coefficient of cracked concrete has a positive linear relation with cracks' maximum width, and the impact of cracks on the permeability coefficient can be neglected when the width is less than 0.18 mm. The width changes of shrinkage cracks significantly affect the impermeability of the concrete, in practical project the allowed maximum width should be determined in accordance with the thickness of concrete cover.

Abstract:To obtain the effects of curing humidity on corrosive medium transporting into concrete, a model between curing humidity and chloride diffusion coefficient was developed according to their relationships with hydration degree and porosity, which was exposed in chloride solution. An experiment was designed to verify the correct of the model, which included ordinary performance concrete and concrete mixed with fibers. All of the specimens were cured in different humidity for 28 days, and then immersed in 8% NaCl solutions for 60 and 180 days respectively. The results showed that reduction of curing humidity could increase the concentration and diffusion coefficient of chloride ions. Saturating curing can reduce the chloride diffusion coefficient by 10~20%, as dry curing increased the value about 14%~29%. This process can be slowed by mixing polypropylene and steel fibers into concrete. The material coefficients were fitted according to the test results and predicted formulas of apparent chloride diffusion coefficient were provided for the concrete after different humidity's curing.

Abstract:To simulate the complex morphology of steel plate and obtain the fatigue notch factor based on real surface topography, the Q235 steel plate was corroded rapidly by salt spray method, and the corrosion surface was measured by three dimensional measurement. Three-dimensional solid model was established, and the surface stress distribution was analyzed by reverse engineering Geomagic Studio software and numerical analysis software ANSYS. Then the numerical results and experimental results were compared. The results show that the error is small enough, which verifies the feasibility of the modeling methods. Geomagic studio can achieve a rapid 3D visual modeling and simulate the corrosion morphology well, combined with ANSYS, it can estimate the fatigue notch factors of various complex morphology components flexibly and efficiently.

Abstract:To obtain the variation of wind speed near ground at the southeastern coastal area of China and its influence factors during the landfall process of typhoons, wind speed samples at 10 m during the landing of two strong typhoons (Typhoon Matsa 0509 and Typhoon Khanun 0515) were recorded by anemometer towers located at the regions of Donghaitang in Zhejiang Province and Luchaogang in Shanghai. Wind speed conversion factors of different time intervals and their probability distribution were calculated based on the sampling wind speeds. It is illustrated that wind speed conversion factors of different time intervals follow generalized extreme value distribution. V_{3 s}/V_{10 min} follows Frechet Distribution, while V_{30 min}/V_{10 min} and V_{1 h}/V_{10 min} follow Weibull Distribution. There are 2 anemometer towers, one is adjacent to the paths of typhoons, while the other one is far away from them. It shows that in typhoons' condition for terrain A, values of wind speed conversion factor keep steady and the probability distribution functions of conversion factors hold similar distribution characteristics during the landing process of strong typhoons regardless of the paths of typhoons, variation of typhoon intensity, the distance between the anemometer tower and the typhoon center and the landfall state of the typhoon. Values for wind speed conversion factors for terrain A in the condition of typhoons based on the analysis of probability statistics provide the assurance of reliability for wind resistant design of structures.

Abstract:To study the wind field characteristics of valley and col terrain and speedup effects in typical positions, Computational Fluid Dynamics (CFD) simulation methodology was employed. The results of an isolated hill obtained from CFD simulations, wind tunnel tests and codes were compared to validate the results of CFD simulation. Valley and col terrain were conducted by CFD. The speedup effects in typical positions of valley and col terrain were analyzed and some design suggestions were given for the top of hill and the inner side of hill bottom. The results show that the speedup effect on the top of hill is the most significant. The speedup effects on the cross-wind plane of an isolated hill are more significant than those on the along-wind plane. The results of CFD simulation match well with those obtained from wind tunnel test. The speedup effect on the top of col is more significant than those on valley and isolated hill. The speedup ratio at the inner side of hill bottom becomes greater with the decreasing distance between two hills. At the inner side of hill bottom under two adjacent hills condition, wind speedup ratio is less than the lower limit of the code for valley terrain and larger than the upper limit of that for col terrain when the distance between two hills is less than half diameter of hill bottom and the height above the hill is less than forty percent of hill height. The speedup effects on the top of hill are almost unchanged under various hill distance conditions. It is not commended to choose cols and tops of hills as the construction sites.

Abstract:To study the structural characteristics and seismic performance of cultural heritage buildings in Kathmandu Valley, an extensive investigation was carried out after Ms8.1 Gorkha earthquake. Brick-timber structures and masonry structures are the two major structural types in Kathmandu, Patan and Bhaktapur Durbar Squares. The structural compositions and characteristics of brick-timber structures and masonry structures were described, and analysis was done for the typical seismic damage such as wall destruction, wooden components destruction, tilt and collapse, and, reasons were studied. The seismic damage degree of cultural heritage buildings was defined, the classification and statistics of damage to the cultural heritage buildings were carried out, and different proportions of damage levels of the two structure types were obtained. The results show that in the total 52 brick-timber structures and 16 masonry structures, the proportion of basically intact or slightly damaged of brick-timber structures is merely 28.8%, and yet the masonry structure is 18.8%, others belong to partially damaged, heavily damaged and collapse, and the seismic performance of brick-timber structures are better than masonry structures. Based on the results of the seismic damage investigations, and compared with the protective principle of cultural heritage buildings, some recommendations on the reinforcement measures of cultural heritage buildings were put forward.

Abstract:To select real strong motions for Chinese seismic safety evaluation work, we disaggregated the result of Chinese seismic safety evaluation work into specified earthquake scenarios considering magnitude, distance and earthquake variation, and then the condition median spectrum was constructed as strong motion selection target. The results based on conditional mean spectrum was compared with uniform spectrum matching result for a real safety evaluation project. The comparison result indicates that the result from the proposed method is consistent with target earthquake scenario, and the proposed method preforms better in matching spectrum shape within the whole period. Finally, a practical real ground motion selection method was proposed for Chinese seismic safety evaluation work.