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(1 清華大學(xué)土木工程系，北京100084；2 中建國(guó)際建設(shè)公司技術(shù)中心，北京100026)

［提要］利用有限單元法對(duì)靜水壓力作用下的圓弧鋼拱、沿水平軸分布的豎向均布荷載作用下的拋物線鋼拱、沿拱軸線分布的豎向均布荷載作用下的懸鏈線拱的平面內(nèi)彈性屈曲進(jìn)行研究，考慮了屈曲前變形、剪切變形及長(zhǎng)細(xì)比的影響。得到了三鉸拱、兩鉸拱、固定拱的彈性屈曲系數(shù)的數(shù)值解。對(duì)數(shù)值解與傳統(tǒng)的經(jīng)典解進(jìn)行了對(duì)比分析，數(shù)值解具有更高的精度。計(jì)算結(jié)果表明，長(zhǎng)細(xì)比大約在20～50的范圍內(nèi)時(shí)，經(jīng)典解具有很大的誤差，用屈曲系數(shù)

經(jīng)典解得到的計(jì)算長(zhǎng)度系數(shù)來(lái)進(jìn)行這類純壓拱的平面內(nèi)穩(wěn)定性設(shè)計(jì)將非常不安全。

［關(guān)鍵詞］等截面純壓鋼拱；彈性屈曲系數(shù)；圓弧拱；拋物線拱；懸鏈線拱

In-plane Elastic Buckling Coefficients of Compression Steel Arch with Uniform Section/Lin Bing^1，2，Guo Yanlin¹ (1 Department of Civil Engineering, Tsinghua University,Beijing 100084, China; 2 Technical Center of China State Construction International Co., Beijing 100026, China)

Abstract:It investigates the elastic in-plane buckling behavior of pure compression perfect steel arches by using finite element method (FEM). The buckling coefficients of fixed, two-hinged, and three-hinged steel arches are obtained numerically for the following cases: circular arches subjected to hydrostatic pressure; parabolic arches subjected to vertical load uniformly distributed on a horizontal projection; and catenary arches under uniform vertical load along the arch axis. The pre-buckling deformations and shearing deformation are considered in the analysis. Conclusions are drawn from comparisons carried out between numerical results and classical results. The classical elastic in-plane buckling theory of arches is not accurate and the FEM analysis is more powerful and acceptable. Using the effective length factor obtained by the classical theory to design pure compression arches will lead to seriously unsafe results with the slenderness ranged from 20 to 50.

Keywords:pure compressive steel arches; uniform section; elastic buckling coefficient; circular arches; parabolic arches; catenary arches