Exact finite beam element for open thin walled doubly symmetric members under torsional and warping moments

Starting with total potential energy variational principle, the governing equilibrium coupled equations for the torsional-warping static analysis of open thin-walled beams under various torsional and warping moments are derived. The formulation captures shear deformation effects due to warping. The exact closed form solutions for torsional rotation and warping deformation functions are then developed for the coupled system of two equations. The exact solutions are subsequently used to develop a family of shape functions which exactly satisfy the homogeneous form of the governing coupled equations. A super-convergent finite beam element is then formulated based on the exact shape functions. Key features of the beam element developed include its ability to (a) eliminate spatial discretization arising in commonly used finite elements, and (e) eliminate the need for time discretization. The results based on the present finite element solution are found to be in excellent agreement with those based on exact solution and ABAQUS finite beam element solution at a small fraction of the computational and modelling cost involved.

In-plane dynamic buckling of duoskelion beam-like structures: discrete modeling and numerical results

In this contribution, a previously introduced discrete model for studying the statics of duoskelion beam-like structures is extended to dynamics. The results of numerical simulations performed using such an extended model are reported to discuss the in-plane dynamic buckling of duoskelion structures under different loading and kinematic boundary conditions. The core instrument of the analysis is a discrete beam element, which, in addition to flexure, also accounts for extension and shearing deformations. Working in the setting of dynamics, inertial contributions are taken into account as well. A stepwise time integration scheme is employed to reconstruct the complete trajectory of the system, namely before and after buckling. It is concluded that the duoskelion structure exhibits exotic features compared with classical beam-like structures modeled at macro-scale by Euler–Bernoulli’s model.

Break even analysis & response of longer span frames with or without post-tensioned beams in multipurpose hall

In this paper analyzed the RC a nd PT Beam against variation in the clear span length of the beam. This work includes the design and estimate of Cost/Beam from 5m span up to 15m span length of the beam. Also, The response of the frame following two variation in its modelling. Initially, The primary model consists of a conventional RCC frame with all beams and columns as RCC. The secondarily model considers peripheral beams as RCC and interior beams with PT. Such as ETABS software used to designed RC beam element and ADAPT-PTRC used to designed PT beam element. However it has been note that variation of cost with respect to the span of beam where the break-even point between RCC and PT technique is approx 7m Span. Also the control on deflection of beam by restrict the depth of beam by using unbonded Post-tensioned prestress concrete beam method. There is very good understand all aspects PT beam better than as compared with to RC beam in deflection against longer span length of beams. This paper gives suggestion about to reach a decidedly conclusion regarding which technique is superior over one another.

Comparison reinforcement design shear wall modelling planar and assembly in elevator shaft

Shear walls modelling as planar or assembly have different assumption in behaviour that will give different responses in forces. Shear wall planar modelling as individual walls which each wall was modelled as a vertical beam. Shear Wall assembly modelling as a combined unit to be represented by one beam element. The application of shear wall assembly is placed in elevator shafts in buildings or stairwell. [1]. In ETABS program, there are two types modelling shear wall are planar walls and wall assemblies. The analysis is based on three types of design section that are Simplified Compression (C) and Tension (T), Uniform Reinforcing and General Reinforcing. The purpose of this study is comparing the planar walls Simplified C and T with planar walls Uniform Reinforcing and wall assemblies Uniform Reinforcing. The conclusion for longitudinal reinforcement are, first, planar walls Simplified C and T is 40 to 96 % larger than wall assemblies, except pier P6 is 28 % smaller, second, planar walls Uniform Reinforcing is larger than 7 to 33 % wall assemblies Uniform Reinforcing, except pier P6 is 39 % smaller, third, the planar walls Simplified C and T, planar walls Uniform Reinforcing transversal reinforcement are 1 to 8 % larger than wall assemblies Uniform Reinforcing, except pier P6 is 51 % smaller.