金华市特殊教育现状的调查研究

特殊教育是对残疾人的一种教育,是社会的人本、民主、公平的反映,是国家及其文明程度的一个窗口。通过对浙江省金华市七所特殊教育学校现状的调查与研究,了解到近几年金华市的特殊教育有很大的发展,但是在办学规模、地理位置、师资力量、硬件设施等方面还存在不足,影响了学龄残疾儿童的入学率与特殊教育的发展速度。故立足于金华市特教的现实问题,提出具有可行性的方法与对策,促进金华市特殊教育事业更好更快的发展。     

秦始皇帝陵文化遗产安全影响因素及价值传播分析

随着"秦始皇帝陵博物院·丽山园"正式对外开放,管理者面临着多重的管理压力,为此以秦始皇帝陵文化遗产地的实际出发,将影响文化遗产管理的安全因素从地理尺度上划分为的遗产地尺度、遗址尺度和文物尺度,着重以这三个尺度为出发点分析了安全监控、遗址风貌、气候环境、人为活动等影响因素,并就如何更好地开展大遗址的文化价值传播提出了自己的见解。     

An Explicit Integration Scheme for Solving Dynamic Problems of Solid and Porous Media

In this article, an explicit integration scheme for dynamic finite element analysis is developed and the formulations for linear elastic solid and two-phase porous media are derived. The accuracy and stability characteristics analyses show this scheme is second-order accurate, which is the same as the Central Difference Method (CDM), and possesses a broader scope of stability within the range of normal damping ratios of media. Comparing with the CDM, this explicit scheme requires no matrix factorization even if a non diagonal damping matrix is included. Therefore, the dynamic finite element equations can be integrated economically provided that the mass matrix is diagonal. To demonstrate the validity of the present scheme, three examples are provided. First, taking a single-degree-of-freedom system as an example, the results obtained by the proposed scheme are compared with the exact solutions. Second, the dynamic responses of half-space saturated porous media, subjected to a concentrated load pulse at the surface, are analyzed. Both examples show that the results obtained by the proposed scheme agree well with the analytical solutions. Finally, the dynamic responses of a plane strain plate due to a load pulse are analyzed, respectively, by the proposed procedure and the commercial code ABAQUS (both implicit module and explicit module), and the CPU costs are compared.     

A Static Nonlinear Procedure for the Evaluation of the Elastic Buckling of Anchored Steel Tanks Due to Earthquakes

Ground-supported steel tanks experienced extensive damage in past earthquakes. The failure of tanks in earthquakes may cause severe environmental damage and economic losses. This study deals with the evaluation of the elastic buckling of above-ground steel tanks anchored to the foundation due to seismic shaking. The proposed nonlinear static procedure is based on the capacity spectrum method (CSM) utilized for the seismic evaluation of buildings. Different from the standard CSM, the results are not the base shear and the maximum displacement of a characteristic point of the structure but the minimum value of the horizontal peak ground acceleration (PGA) that produces buckling in the tank shell. Three detailed finite element models of tank-liquid systems with height to diameter ratios H/D of 0.40, 0.63, and 0.95 are used to verify the methodology. The 1997 UBC design spectrum and response spectra of records of the 1986 El Salvador and 1966 Parkfield earthquakes are used as seismic demand. The estimates of the PGA for the occurrence of first elastic buckling obtained with the proposed nonlinear static procedure were quite accurate compared with those calculated with more elaborate dynamic buckling studies. For all the cases considered, the proposed methodology yielded slightly smaller values of the critical PGA for the first elastic buckling compared to the dynamic buckling results.     

A Damage Index for the Seismic Analysis of Reinforced Concrete Members

This article proposes a damage index for the seismic analysis of Reinforced Concrete members using the hysteretic energy dissipated by a structural member and a drift ratio related to failure in the structure. The index was calibrated against observed damage in laboratory tests of 76 RC column units under various protocols. Values obtained in this calibration had acceptable agreement with the levels of damage observed in the test specimens. An analysis of the parameters involved in the definition of the proposed damage index shows the importance of displacement history in the drift ratio capacity of structures.     

Approximate Methods for Estimating Hysteretic Energy Demand on Plan-Asymmetric Buildings

The first step in a hysteretic energy-based design approach of performance-based design is the estimation of hysteretic energy demand in the structure. A nonlinear response-history analysis of the multi-degree of freedom model gives an accurate estimation, but it is not suitable for adopting in design. Two alternative methods, based on the concepts of modal pushover analysis (MPA) and 2D-MPA, are proposed in this article for uniaxial plan-asymmetric structures. Application studies show that both methods are efficient. While the 2D-MPA-based method is more accurate, the MPA-based method is more suitable for design adoption. Significant conclusions are given for prospective application of these methods.     

Numerical Fragility Analysis of Vertical-Pile-Supported Wharves in the Western United States

This study develops seismic fragility curves for vertical-pile-supported wharves commonly found in the western United States. Nonlinear time-history analyses of a two-dimensional numerical model under two ground motion suites are performed. The results show that the jumbo container cranes increase by 10.8% in the wharf deck drift. By using the experiment-based limit states, the proposed fragility curves demonstrate that, at a PGA of 0.50 g, the probabilities of exceeding slight, moderate, extensive, and complete limit states are approximately 23.0%, 7.0%, 4.0%, and 3.0%, respectively, while at a PGA of 1.00 g, the exceeding probabilities increase to 44.0%, 19.0%, 14.0%, and 11.0%, respectively.     

A Modified Capacity Spectrum Method with Direct Calculation of Seismic Intensity of Points on Capacity Curve

A direct methodology for solving the seismic intensity of each point on the capacity curve is proposed. By utilizing the procedure, a continuous curve between the structural response and the seismic intensity, the structural response function, can be easily generated. Unlike previous procedures that search for the performance point of a determined seismic intensity, the proposed methodology easily draws the full curve without iterations. The procedure is applicable to both a smooth design spectrum and an actual response spectrum. Examples indicate the methodology is accurate and fast, and convenient to be combined with existing procedures, such as Modal Pushover Analysis.     

Applicability of Pushover Methods to the Seismic Analyses of an RC Bridge,Experimentally Tested on Three Shake Tables

The applicability of different pushover methods was analyzed on the example of a bridge, which was experimentally tested on three shake tables at the University of Nevada, Reno. The response of the bridge was quite complex. The intensity as well as the direction of the deck torsional rotations varied significantly, depending on the seismic intensity. At the low intensities, all the employed pushover methods estimated the displacements of the deck very well. In the case of strong earthquakes, the advantages of multi-mode and adaptive methods was demonstrated.     

Seismic Demand on Shear Panel Dampers Installed in Steel-Framed Bridge Pier Structures

This study is aimed at investigating the demand on shear panel dampers (SPDs) installed in steel structures under strong earthquake motions to serve as guidance for the recommended capacity of SPDs in seismic design. For this purpose, an extensive dynamic analysis is carried out on steel bridge pier structures with SPD devices. To describe the restoring force characteristics of SPDs, the analysis uses a newly developed combined hardening model based on experimental data. The seismic demands made on SPD devices are examined and then summarized to give recommended values for determining the necessary deformation capacity of SPDs.