Eccentric Vertical Load Research Articles

動揺歯を含むブリッジの光弾性的研究

The present study photoelastically analysed stress distribution in the alveolar bone around the abutment teeth for a bridge involving mobile teeth. The mobile teeth in this study were limited to those which were lack of support because of their increased crown-root ratio. Four types of 〓 bridge models for a case 〓 being absent and 〓 mobile were used : type A, with normal 〓 and mobile 〓 ; type B, with normal 〓 and normal 〓 ; type C, with mobile 〓 and mobile 〓 ; and type D, with mobile 〓 and normal 〓. The mobility of a single mobile tooth was characterized by a typical Moire fringe at its cervical portion in addition to its root apex under an eccentric vertical load. When 〓 was connected with other abutments by a rigid bridge, the mobility of 〓 was markedly decreased even if 〓 and/or 〓 were mobile. The analyses of stress distribution showed that the applied load through the bridge was primarily supported by the alveolar bone around 〓 in and type. It was suggested from the foregoing results that the immobility of 〓 might be essential for minimizing the mobility of the abutment teeth.

Design of reinforced masonry walls and columns for gravity loads

The ultimate strength of reinforced masonry compression members subjected to axial or eccentric vertical loads is the main concern of the paper. As an initial step, the literature is reviewed so as to arrive at reasonable assumptions relating to the stress–strain properties of the material; these are necessary to define the load–moment interaction curve for a short column or wall. A method that can account for the weakening effect of slenderness is also discussed. These two fundamental components of the procedure are then judged relative to experimental test data. Axially loaded walls are modelled quite well but the theory is conservative for walls tested eccentrically. Although the inclusion of a strain gradient factor and consideration of nonlinear behaviour would improve analytical predictions for the latter case, these extra factors are not applied to the results due to a lack of definitive knowledge relating to the latter.

Strength of Load Bearing Masonry Walls

A theory is presented, for the rational analysis of masonry walls under eccentric vertical compressive load, or under a combination of vertical compressive and transverse load. The theory is based on established concepts, which have been modified to account for the properties of masonry. Similar methods of rational analysis have been adopted for the design of steel columns and are in the process of being adopted for reinforced concrete columns. An investigation of the results of 192 tests of full-scale walls of various types of masonry construction established the feasilibity of applying this theory to closely predict the strength of these walls. The analysis accounts for variables not presently considered in the design of masonry structures. The correlation between test results and theory is illustrated by several typical examples.

Buckling of load Unsupported Timber Piles

The results of a pile loading test made on a group of four long, unsupported, timber piles in order to determine their ultimate buckling capacity are presented. The test results confirmed that the ultimate bearing capacity of the long timber wharf piles was governed by the buckling capacity of the unsupported section of the pile. The buckling capacity of the long piles, acted on by an eccentric vertical load, can be determined theoretically with satisfactory accuracy, using the appropriate form of the secant equation. Appreciable lateral support was provided to the embedded part of the timber piles by the soft foundation soils that exist at the site. The computed depth below the mud line to the apparent point of fixity ranged from 6 ft to 11 ft. Conventional practice for soft foundation soils is to assume fixity at 10 ft depth. The test results confirm this practice to be reasonable.