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No description available.

No description available.

No description available.

This investigation deals with the possibility of local failure in 4" aluminum I beams due to insufficient bearing area at end reactions and includes an investigation of the column theory of such failure. A comparison is made between the failure of two types of aluminum alloy, 17-ST and 65-ST. The application and determination of design formulae to determine the width of bearing necessary is explained and demonstrated for the 4” I beam.

The severity of the Canadian winters has, in the past, and does now, affect the construction business. Not only does it lower the efficiency of the working men, it affects the quality of the finished product. This is particularly noticeable in concrete construction where: 1.The formwork is erected more carelessly. 2. Batching weights are less accurate due to human failure and frost affecting the moving parts of the scales. 3. Placing and vibrating are poorly done due to the men being cold.

Controlled-stress, consolidated-undrained triaxial tests with pore pressure measurements were performed on partly saturated bentonite specimens prepared by two different methods of compaction, static and kneading, to give different structural arrangement of the sail particles. The results indicate that the static method employing higher compaction pressure tends to align particles in a more horizontal array as a result of the larger shear strains induced. Samples prepared by the same method of kneading compaction but using different compactive effort of twenty and ten blows with a 20-pound tamper on each of the five layers designated 20-20-5 and 10-20-5 samples respectively show that the less dense 10-20-5 samples have a higher pore pressure response than the 20-20-5 samples as predicted.

The shear strengths of silt samples of a given porosity were compared for three different types of triaxial test, under varying conditions of lateral pressure, drainage and saturation. The three types of triaxial test conducted were: I) Unconsolidated drained test on dry silt. II) Unconsolidated undrained test on partially saturated silt. III) Unconsolidated drained test on a partially saturated silt. The maximum strength was exhibited by the dry silt and was considered to be primarily a function of the effective stress on the contact area.

The results of model footing tests on a remoulded clay are described. For the clay used in these tests, the observed deformations and bearing capacities were not in agreement with those expected from the conventional bearing theories. The observed bearing capacity was about 25 percent less than that given by the latter theories, due to a punching or local shear failure. An approximate theory developed by Bishop et al (1945), to determine the load required to force a punch into a semi-infinite cohesive mass, was examined. The bearing capacity determined from this theory was in reasonable agreement with the results of the model tests, and also a limited amount of other data which could be examined. On the basis of these limited results, a relation is suggested for the bearing capacity of surface footings on saturated clay which includes, and predicts from the stress-strain properties of the clay, the case where a local shear failure occurs.

Tests on four concrete beams with transverse-longitudinal steel ratio varying from zero to 1.86 are reported. The strength of the rectangular reinforced concrete beams, all of which fail due to direct shear and torsion, agree favourably with the tensile strength of concrete determined from indirect tension tests. Initial cracks occurred in all the beams at a load corresponding to a combined shear stress of 346 psi in an unreinforced section under combined bending, shear and torsion. Results indicate that the shear reinforcement ceases to be fully effective as the Pt/p+p' ratio approaches and exceeds unity. Moreover the concept of a transition from elastic to plastic states of stress is proved by the results. Expressions have been derived for the stresses and unit angle of rotation for the central section of the beam remaining plane. The results of the limited number of tests appear to agree well with the modified theory.