Leslie K. Guice

MEMBRANE ANALYSIS OF FLAT PLATE SLABS

Tests of 47 one-way reinforced concrete slab strips subjected to uniformly distributed loads are reported. The slabs are typical of those used in the flat-plate designs of protective construction. An analytical procedure modified from previous investigations is used as basis for determining the peak flexural capacity of slabs. Results of compressive and tensile membrane analyses are compard and shown to predict reasonably the peak capacity and tensile membrane response.

An analogous model for slabs using a truss element

Abstract Restrained reinforced concrete slabs have load-deflection curves which are similar to those for shallow shells. These curves have a distinct instability following an initial peak. However, most analytical procedures for slabs do not take into consideration the effects of nonlinear geometry, but attribute the instability to material nonlinearity. In this paper, a simple truss element model which is typically used in the stability analysis of thin shells is shown to predict the total load-deflection curve for a restrained slab. The element is formulated with a small initial angle of inclination which is related to the height of the internal arch formed in the slab during early deflections. Solution of the nonlinear equation is accomplished with the Newton-Raphson method. Results of analyses demonstrate a reasonable similarity with recent experimental data.

Creep Test of Cured-In-Place Pipe Material Under Tension, Compression, and Bending

Inexpensive and easily fabricated long-term creep test devices have been designed and built in order to identify the long-term creep behavior of cured-in-place pipe (CIPP) material under tension, compression, and bending. A special device for testing curved specimens has been designed, built, and evaluated. Loads were applied for 3000 h, and the deformations of CIPP specimens were recorded. Findleys equation, which has been successfully used to predict the creep behavior of plastics for more than 25 years, was used as a baseline for data analysis. The results from Findleys approach were compared with the results from the analyses by theoretical and log-fit methods. The comparison of the three approaches shows that the best estimation of 3000-h creep moduli can be obtained by using the log-fit method.