起重機伸臂格子桁架設計改善之探討

Study in Modification of Lattice Design of a Crane Boom

格子桁架起重機伸臂的鋼結構設計，採用了幾種固定的幾何形態，由強度分析的結果，可以比較其格子桁架的形狀及桿件的排列方式是否較佳，然而，格子桁架式起重機的空間結構複雜，以傳統的手工計算，結果與實際情形相去甚遠。因此，本文強調使用有限元素方法分析，針對結構強度最弱的伸臂部，探討形狀及配置改變時，結構強度受到的影響，以建立格子桁架式起重機結構設計改善的準則。

The lattice-boomed crane, e.g. hammer-head tower crane, is one of the most common used cranes in construction sites. The structural design of a boom is not an easy task due to geometrical complication. In convention, design computations proceeded manually by using over-simplified model yields a great disparity between experimental results and design computations. Consequently, this study proposed a numerical method by using finite element analysis. The optimized structural design of a boom for lattice-boomed crane can be achieved by analyzing the stress distribution with various lattice layouts and positions of tension rope. This new approach provides an improvement in structural design of a lattice-boomed crane and a reference for design criteria.