Discussion Of Some Problems On Seismic Performance Of Tall Precast Reinforced Concerte Building In Hong Kong

Experiences of minor vibrations of buildings in Hong Kong caused by the recent near-field and far-field earthquakes alert the general public that Hong Kong is not free from earthquake attacks. In fact, Hong Kong has been identified as a region of moderate seismicity. However, almost all local residential buildings have not been designed for any seismic resistance. This problem is getting worse as there is a trend of incorporating many precast concrete structural elements in local buildings to achieve high quality control, green construction environment, and increased speed of construction. Painful previous earthquake lessons indicate that buildings involved many precast elements and connections likely exhibit inferior seismic performance accommodate large cyclic deformations, if they are not properly designed for earthquake resistance. So far, a quantitative assessment of the precast systems on the seismic performance of local buildings has not been reported.The objective of thesis is to assess the seismic performance of Hong Kong buildings used precast elements. Through numerical experiments and result analysis, then different codes reviewed, the following problems are analyzed. And some applicable results are obtained.1. Seismic design requirements for nonstructural building components of four major building codes, including the Uniform Building Code, the New Zealand Building Code, Eurocode 8 and nonstructural provisions used in China, were reviewed in this study. It discussed the design philosophy and provisions of different seismic codes, and compared design lateral force recommended in these codes. Most of these codes provide simplified method to obtain design seismic force which depends on the response of its supporting building, size and weight of the element, relative location of the element in the building, flexibility of the nonstructural elements, etc.2. Results of the seismic performance assessment of a typical structural system in Hong Kong that has been used in a 41-story reinforced concrete building are presented. And the results were compared to the structural system which does not include structural facades. The parameters story drift and story shear were study to reveal the influence of structural facade on building.3. Finally, this thesis presents critical review of recommendations of well established codes regarding design and detailing aspects of beam column joints. The codes of practice considered are ACI 318-05, NZS 3101 Part 1:1995 and the Eurocode 8 and GB50011-2001. The mechanisms involved in joint performance with respect to member depth and shear transfer are critically reviewed and discussed in details. The factors impacting the member depth within the joint appears to be well related to the level of axial load and the amount of transverse reinforcements in the joints. The parameters that affect the shear demand and shear strength of the joint are explained. The design of shear reinforcement within the joint and its detailing aspects are also discussed. A significant amount of ductility can be developmented in a structure with well designed beam-column joints where in the structural members could perform satisfactorily as per the capacity design principles.