Horizontal construction joints for massive high-head structures: Fid-Bau Portal

Horizontal construction joints for massive high-head structures

Ginzburg, Ts. G. / Lavrinovich, E. V. / Zinchenko, N. A. / Shutukov, V. N.

Conclusions 1. The intensity of compaction of a concrete mix and its permanent control are of decisive importance in obtaining firm and strong joints. 2. With proper selection of the proportions of the concrete mix, preparation of the joint, and compaction of the placed concrete, all the possible technical methods (placing of the mix without an underlaying layer, placing on an underlying mix layer, and placing on a soft concrete layer) ensure the required strength and watertightness of the horizontal construction joints. 3. When modem large vibrators are used, permanent control of the concreting and especially of the compaction of the concrete permit eliminating the underlying layer of mortar or soft concrete mix, with the result that the concreting operations are simplified and their cost lowered. This is especially important in the case of intense work on large structures. 4. There are sufficient bases for revising Paragraph 217 of the “Technical Rules for Concreting Operations in the Construction of Hydraulic Structures,” in which the placing of an underlaying layer of mortar or plastic concrete is made mandatory. In such a revision, the technical procedures for concreting of the first lift of massive concrete blocks without underlying layers should be regulated. According to the preliminary estimates, this would yield an annual saving per each million m3 of concrete of 190,000 rubles and would result in a reduction in the labor use by 130,000 man-hours.