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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 44 Abstracts search results
Document:
SP54-37
Date:
January 1, 1977
Author(s):
Carlos L. Corrales, Edwin Quesada, and Helmut G. Kobler
Publication:
Symposium Papers
Volume:
54
Abstract:
Costa Rica is one of the five Central American countries and, because of its temperate climate and mountainous topography, it is often referred to as the Switzerland of the Americas. For the past twenty years, the Government of Costa Rica has been aggresively developing its considerable hydroelectrical resources through an autonomous power authority called "Instituto Costarricense de Electricidad" (ICE). The use of shotcrete as temporary and permanent underground support has greatly contributed towards the successful completion of a number of hydroelectric projects constructed by ICE during the last decade.
DOI:
10.14359/18050
SP54-43
Robert E. Mason
While organizing this conference, the disappointing discovery was made that very few important shotcrete projects had been performed in North America in the last three years. However, as evidenced by the papers given at the conference, considerable work of great interest has been performed in many other parts of the world. In Europe the use of the New Austrian Tunneling Method (NATM) seems to be spreading rapidly, even to countries that pride themselves on their individuality.
10.14359/18056
SP54-31
Jonas Holmgren
The investigation presented in this paper is the First step in a joint project between the Royal Swedish Fortifications Administration (FortF) and the Swedish Rock Mechanics Research Foundation (BeFo). Its aim is better knowledge of shotcrete as a means of rock strengthening. If this aim is reached considerable economic savings could be made since the thicknesses of shotcrete used in practice probably are overestimated because of this lack of knowledge and the psychology of safety.
10.14359/18044
SP54-39
Alberto Marulanda and Luis F. Eslava
This paper refers to the application of shotcrete in tunnels driven through soft rocks which behave as squeezing ground. More than 15 km of tunnel have been successfully driven through those rocks using shotcrete as the main stabilization measure. The described experiences refer only to a small percentage of the total excavated lengthj, where local problems and cracks were evident in the shotcrete lining. The observational program which included instrumentation and observation of shotcrete behavior, indicated that shotcrete failure in soft rocks could be due to: a. Stress concentrations during the redistribution process around the tunnel that induce high tensile strains and cracking of the shotcrete. b. Inability of the shotcrete lining to resist the squeezing pressure when acting as acontinous lining (compression ring) with a compressive shear mode of failure.
10.14359/18052
SP54-25
W. Mayrhauser
The NATM is a double shell building mehtod consisting of the shotcrete outer arch (reinforced by welded wire fabric and steel rib sections) and the systematically anchored rock carrying ring. The rock carrying ring is the primary supporting element and thus of the greatest importance. These two shells - the shotcrete outer arch and the rock carrying ring - have to be dimensioned in such a manner that the gound reaches a permanent equilibrium. To ascertain this, extensive measuring is required. These measurements are a fundamental criterion of the NATM and consist of: a) Roof conolidation bolts b) Convergency measurements c) Extensometer measurements d) Measuring anchors. These measurements are taken continuously in the course of the advance on site.
10.14359/18038
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