建筑类专业英语论文

Building and Environment 40(2005)1689–1696

Modified braced wall system with pre-stressed wale for excavation in

urban areas

Gwang-Hee Kim a ,Ung-Kyun Lee b ,U-Yeol Park c ,Jae-Yeob Kim d ,Kyung-In Kang b,Ã

a

Department of Architectural Engineering,Mokpo National University,61,Dorim-Ri,Chunggye-Myon,Muan-Gun,Chonnam 534-729,

Republic of Korea

b

Department of Architectural Engineering,Korea University,5Ga,Anam-Dong,Sungbuk-Gu,Seoul 136-701,Republic of Korea c

School of Architecture,Youngsan University,150,Junam-ri,Ungsang-eup,Yangsan,Gyeongnam 626-847,Republic of Korea

d

Department of Architectural Engineering,Kyungil University,33Buho-ri,Hayang-Up,Gyeongsan-Si,Gyeongsang buk-do 712-702,Republic of Korea

Received 1September 2004;accepted 2December 2004

Abstract

Excavation works in soft clay require the installation of a retaining wall together with a means of holding the retaining structure in position.However,the traditional braced wall system (TBWS)used for that purpose unfortunately narrows the spacing between struts during excavation works.To address the issue,this paper introduces the modified braced wall system (MBWS)for widening the horizontal intervals between struts.Case studies were performed to validate the MBWS by comparing its costs,schedules,constructability,and safety to those of the TBWS.The results showed that the MBWS was more effective than the TBWS.r 2005Elsevier Ltd.All rights reserved.

Keywords:Excavation work;Modified braced wall system (MBWS);Retaining wall

1.Introduction

In recent years,growing land prices and lack of space have necessitated deeper and larger basement excavation in Seoul,Korea,even in unfavourable subsoil,and more often in restricted spaces.In Seoul,the subsoil is generally soft clay.A deep excavation in such soft soil can cause large settlements and horizontal movements of the ground around the excavation [1].Horizontal movements are also a major factor to consider during excavations [2].Therefore,it is necessary to provide protection to existing buildings adjacent to the con-struction site,because excavation may damage them [3].Excavation works in soft clay require the installation of a retaining wall structure together with a means of holding the retaining structure in position.Thus,the

selection of the most appropriate system,at the project planning stage,should encompass safety,economic,constructability,and pollution prevention issues [4].During excavations,stiff support systems should be placed where needed,to protect adjacent buildingsand utilities.System stiffness is defined in terms of the flexural stiffness of the wall and of the support spacing.However,the support spacing is more important than wall stiffness in defining system stiffness and helping control movements [5].

In Seoul,the usual support system is the soldier pile with lagging,and the bracing or tieback system [6].Tieback supports are commonly preferred for large excavationsbecaus e they provide a relatively unob-structed work area.However,these have three main disadvantages [7]as follows.(1)It is necessary to obtain permission to trespass into the adjacent subsoil.(2)One may encounter public utilitiesburied underground.(3)The tieback’sanchor boltsare left in place after construction is completed,as it would be excessively costly if not physically impossible to remove them.For

/locate/buildenv

0360-1323/$-see front matter r 2005Elsevier Ltd.All rights reserved.doi:10.1016/j.buildenv.2004.12.007

ÃCorresponding author.Tel.:+8229215920;fax:+8229234229.

E-mail addresses:gwanghee@ (G.-H.Kim),

dldndrbs@korea.ac.kr (U.-K.Lee),wypark@ysu.ac.kr (U.-Y.Park),kimjy67@kiu.ac.kr (J.-Y.Kim),kikang@korea.ac.kr (K.-I.Kang).