SuperMap Object在地震灾害预估中应用浅析

用基于易损性矩阵基础上的城市震害预估方法，计算调整损失比后的经济损失，其中包括等震线模型、城市震害模型及建筑物直接经济损失模型等的设计与实现，并针对我国城市的具体情况，编制了一套《城市震害预估及房屋易损性矩阵数据库实时更新软件》，为我国震害预估技术的深层次开发打下坚实的基础。     

场地类别划分与抗震设计反应谱的讨论

介绍了新的抗震设计规范(2001—07—20发布，2002—01—01实施)中场地类别划分和地震影响系数的有关内容，指出其中一些不相协调之处。最后，针对不同的问题建议相应的解决办法。     

Evaporite Dissolution Subsidence in the Historical City of Calatayud,Spain: Damage Appraisal and Prevention

Calatayud in NE Spain is an historically important city built on recent alluvial deposits underlain by gypsum and other soluble rocks. Since its foundation by the Muslims in 716 A.D., the city development has been strongly influenced by geohazards including flooding, subsidence and slope movements. Most of the flooding problems have been mitigated by diversion of the local drainage. However, dissolution of the evaporite bedrock in the urban areas continually causes subsidence and triggers rock-falls from the gypsum cliffs overlooking the city. Subsidence is also caused by the hydrocollapse of gypsiferous silt in the alluvial fan deposits. Building damage in the city was surveyed using a classification scheme developed originally to record damage in British coal mining areas. The Calatayud damage survey shows that the worst building subsidence is concentrated along the line of a buried channel that runs underneath the gypsiferous silt alluvial fan. Natural subsurface drainage causes the dissolution and subsidence, which is aggravated by leakage from water and sewage pipes. Some building damage has been exacerbated during reconstruction by incomplete piling leaving buildings partially unsupported. Mitigation measures include the control of water leakage by the installation of flexible service pipes. Careful construction techniques are needed for both conservation and new developments, especially when piled and minipiled foundations are used. Geomorphological mapping is cost-effective in helping to locate and avoid the zones of subsidence for future development.     

应用硅化-水泥灌浆法快速处理地基

合肥市望江东路某小区因新建住宅楼使相邻建筑物基础产生不均匀沉降,造成墙体、地面多处裂缝,裂缝的发展很快,采用硅化-水泥灌浆法快速地阻止了不均匀沉降,保证相邻建筑物安全使用.     

历史大震与泉州古建筑塔寺桥类的结构抗震

研究泉州市一些经历了1604年泉州海外7．5级大震并保存至今的典型塔、寺、桥类建筑的结构抗震,同时探讨这次大震对这些古建筑可能产生的地震影响,及这些古建筑在场地特征、结构设计、材料强度、施工工艺等方面与结构抗震有关的问题。     

Effects of torsion factors on simple non-linear systems using fully-bidirectional analyses

An ensemble of earthquake records is used to carry out non-linear analyses of simple torsionally unbalanced systems considering both resisting elements and earthquake components along two perpendicular directions. These fully bidirectional analyses are focused to study the effect of the following factors: (i) seismic-force reduction factor; (ii) factors α and δ used to compute the design eccentricity; (iii) initial lateral period; and (iv) initial stiffness eccentricity. Results indicate that the amplification factor α can be specified as a function of the force reduction factor, the lateral uncoupled period, and the stiffness eccentricity. It is concluded that the coefficient δ depends on the lateral period, the stiffness eccentricity, and the geometrical eccentricity. It was observed that negative shears caused by torsion should be neglected in the design of the stiff element, particularly in the case of systems with large stiffness eccentricity. Results suggest that additional studies should be performed to verify the assumed (partial) equivalence between unidirectional (resisting elements and earthquake components along one direction only) and fully bidirectional analyses to study building torsion problems. Copyright © 1999 John Wiley & Sons, Ltd.     

Experimental investigation of adjacent buildings connected by fluid damper

Dynamic characteristic and harmonic response of adjacent buildings connected by fluid damper were experimentally investigated using model buildings and fluid damper. Two building models were constructed as two three-storey shear buildings of different natural frequencies. Model fluid damper connecting the two buildings was designed as linear viscous damper of which damping coefficient could be adjusted. The two buildings without fluid dampers connected were first tested to obtain their individual dynamic characteristics and responses to harmonic excitation. The tests were then carried out to determine modal damping ratios of the adjacent buildings connected by the fluid damper of different damping coefficients and at different locations. Optimal damper damping coefficient and location for achieving the maximum modal damping ratio were thus found. The measured modal damping ratios and harmonic responses of the building-fluid damper system were finally compared with those from the individual buildings. The comparison showed that the fluid damper of proper parameter could significantly increase the modal damping ratio and tremendously reduce the dynamic response of both buildings. Copyright © 1999 John Wiley & Sons, Ltd.     

Effects of structural walls on the elastic–plastic earthquake responses of frame–wall buildings

Effects of structural walls on the elastic–plastic earthquake response of short- to medium-height reinforced concrete buildings were investigated. The analytical model consists of independent lumped mass systems representing walls and frames connected at each floor. The wall structure undergoes flexural as well as shear deformation and fails in shear at relatively small story drifts, the frames deforming only in shear. As a measure of structural damage, the ductility factor responses of frame structures were calculated for different combinations of base shear coefficients for the frames and walls. In buildings with relatively weak frames, the installation of structural walls did not improve the large plastic response of the frames up to the point where the walls were unfailed in shear and the ductility factors of the frame structure were suddenly reduced to a very small number. For relatively strong frames, however, the response displacements decreased gradually as the number of walls increased, whether or not the walls failed. Empirical formulas for the required base shear coefficients of the walls and frames which gave a target ductility factor response also were derived for two particular groups of accelerograms. These equations should be of practical use in designing frame-wall type buildings and in retrofitting damaged buildings. Copyright © 1999 John Wiley & Sons, Ltd.     

Dynamic characteristics and seismic response of adjacent buildings linked by discrete dampers

Coupling adjacent buildings using discrete viscoelastic dampers for control of response to low and moderate seismic events is investigated in this paper. The complex modal superposition method is first used to determine dynamic characteristics, mainly modal damping ratio and modal frequency, of damper-linked linear adjacent buildings for practical use. Random seismic response of linear adjacent buildings linked by dampers is then determined by a combination of the complex modal superposition method and the pseudo-excitation method. This combined method can effectively and accurately determine random seismic response of non-classically damped systems in the frequency domain. Parametric studies are finally performed to identify optimal parameters of viscoelastic dampers for achieving the maximum modal damping ratio or the maximum response reduction of adjacent buildings. It is demonstrated that using discrete viscoelastic dampers of proper parameters to link adjacent buildings can reduce random seismic responses significantly. Copyright © 1999 John Wiley & Sons Ltd.     

Adaptive base-isolation of civil structures using variable amplification

Semi-active dampers are used in base-isolation to reduce the seismic response of civil engineering structures. In the present study, a new semi-active damping system using variable amplification will be investigated for adaptive baseisolation. It uses a novel variable amplification device （VAD） connected in series with a passive damper. The VAD is capable of producing multiple amplification factors, each corresponding to a different amplification state. Forces from the damper are amplified to the structure according to the current amplification state, which is selected via a semi-active control algorithm specifically tailored to the system＇s tmique damping characteristics. To demonstrate the effectiveness of the VAD-damper system for adaptive base-isolation, numerical simulations are conducted for three and seven-story base-isolated buildings subject to both far and near-field ground motions. The results indicate that the system can achieve significant reductions in response compared to the base-isolated buildings with no damper. The proposed system is also found to perform well compared to a typical semi-active damper.