LAPBOX

Legacy software from 1986 for the analysis of curved nonprismatic reinforced and prestressed concrete box girder bridges. Source code in FORTRAN and related reports can be downloaded from the earthquake engineering online archive maintained by University of California Berkeley.

LAPBOX: Linear Elastic Analysis of Box Girder Bridges

Choudhury, Deepak

Department of Civil Engineering, University of California, Berkeley, 1986,

LAPBOX is an implementation of a numerical procedure for the analysis of curved nonprismatic reinforced and prestressed concrete box girder bridges. Thin-walled beam theory and the finite element method are combined to develop a curved nonprismatic thin-walled box beam element. The cross section of the element is a rectangular single-cell box with side cantilevers. The axis of the element is curved in plan. The cross sectional dimensions vary along the element axis. Eight displacement degrees of freedom, including transverse distortion and longitudinal warping of the cross section are considered at each of the three element nodes. Small displacements and small strains are assumed in the element formulation. Prestressing, consisting of post-tensioned bonded tendons in the longitudinal direction, is considered. The tendons are idealized as straight prestressing steel segments between nodes of the box beam elements. Friction and anchorage slip losses are considered.