A special application of Bassali's solution for transverse flexure of thin elastic plates supported at several points is presented for the case of symmetrical bending. Equations for moments , shearing forces. and stresses are developed which may be useful for design purposes. The ex perim e ntal results although limit ed in quantity are in good a.greement with the theoretical predic tion s.

(Jul y 8, ] 966)Bassali 's ge ne ral th eo ry fo r the fl exure of th e thin c irc ul a r elastic pl a te suppo rted a t a n a rbitrary numbe r of points a nd subj ec ted to tran sverse load ove r a n ecce ntri c circle is spec ialized to th e case of a centrally load ed pla te s upporte d at points equally s paced on a c ircle co nce ntri c with th e ce nte r. Simplified me thod s fo r approximating th e res ults predi cted by th e more complic ated theo re ti cal ex· pressions for defl ec ti o n are prese nted along with th e ex pe rim e ntal res ult s from 138 tes ts . Both th e ex pe rimental res ults a nd th e simplifi ed equati ons a re co mp a red with the th eo ry and agree me nt is fo und to be good. Key Word s: Bassali 's th eo ry, co nce ntri c loading, circ ul a r plates, defl ec ti on, elast ic it y, exp eri · me ntal, fl exure, point supp orts, simplified app roximate soluti ons, thin plates. Introducti onThe de termination of the defl ec tion of a centrally loaded circular plate supported at points equally spaced on a circle concentric with the center has long bee n an important structural analysis proble m. In the past th e analysis of thi s problem was us ually limited by the assumption that th e point s upports were numerou s e nough to co ns titute a simple co ntinuous line support. Nadai [1] J presented a theory for the deformation of a circ ular plate s upported at several points with central point load or uniform load whic h was an improveme nt in that it recognized the errors involved in the afore me ntioned assumption. Unfortunately, Nadai's point s upports were located alon g the circumference of the plate. To some exte nt thi s limited the utility of the theory, as this me thod of support is unus ually diffic ult to realize in practi cal s tru ctures .More recently, Bassali [2] has give n the solution of the problem of fl exure of a thin circ ular elastic plate s upported at an arbitrary numb er of points whic h may b e located anywhere within the pl a te periphery, and loaded over a circular area lying anywhere within the boundary of the plate. Implicit in the work of Bassali is the solution of the problem of the centrally loaded plate supported at points equally spaced on a circle concentric with a central load. It may be noted . that the theory accounts for the cons training effec t of an annular region of the plate which overhangs the support circle and is otherwise free from restraint. This paper deals with the s p ecializ~ti~n of that part of the Bassali theory necessary to s· olve the particular proble m described above, and presents the rather tedious theoretical expressions for the defl ec tion at the ce nter of the plate and at a point midway between s upports locate d along the support circle. Since these expressions require considerable e ffort to e valuate, simplified methods of approximating the center d e flection may b e d esirable for d esign purposes. Therefore simplified expressions for ce nter de fl ection, based on the results of the exact theory, are given. Experim...

that the NBS staff has optimum accessibility to the scientific information of the world, and directs the public information activities of the Bureau. The Office consists of the following organizational units:

Because of the concern for safety in the storage and use of gasoline and other flammable liquids around the home, this study was made to determine if standards can be established to minimize the flammable liquid hazard by controlling or standardizing the containers. Attention was focused on performance standards for stability, leakage, carrying handle strength, and pour spout strength. In general, it was found that the technology involved in existing voluntary standards for safety cans could be applied to flammable liquid containers for home use for all of the above factors except pour spout strength.

No abstract

Four box girders with lap welded splices were tested to determine the effect of rotation of eccentrically loaded lap welded reinforcing bars on the lateral rigidity of the splice and precast thin-shelled concrete framing members. Each specimen was made of six precast thinshelled elements that were welded and spliced together to form a hollow box girder 1-by 2-ft in cross section and 8 ft 10 in. long. These girders were used to compare the relative rigidities of lap welded splices with and without transverse reinforcement.The comparative results of flexural tests of these girders indicate that there was little difference in the observed lateral displacements up to stresses in splices of about 35,000 psi.However, at higher stresses, the lateral movement of the end portion of the girders and the concrete surrounding the splices was significantly greater in the girders which contained no transverse reinforcement .

This report presents a summary of the findings in the study of the properties of twenty nine 5>-by 5-ft prestressed cellular slabs tested under concentrated loads.Deflections, strains, crack patterns, and loadcarrying capacities were recorded. The data reported herein indicate that the primary mode of failure is diagonal tension, that suitable jointing material between the units is necessary, that web reinforcement of the units is required to increase the load-carrying capacity of the slabs, and that the proper selection of jointing material is important.

As a continuation of the study of the properties of prestressed cellular slabs, a nine celled unit of cement-asbestos was developed, and a slab composed of 16 of these units was tested. Since concrete cannot in itself develop high enough tensile strengths to withstand the diagonal tension encountered in slabs of this kind, cement-asbestos was used.