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International Concrete Abstracts Portal

Showing 1-5 of 64 Abstracts search results

Document: 

SP70-55

Date: 

January 1, 1981

Author(s):

Douglas Dunbar

Publication:

Symposium Papers

Volume:

70

Abstract:

Major advances in the field of tunnelling have been achieved in the post-War period, particularly in relation to machine mining and the development of precast concrete segmented linings. The principal challenge which must now be overcome is the perfecting of waterproofing systems for segmented linings. . .The other waterproofing components: interior linings, patching techniques and the development of superior concretes could form the basis of a subequent paper on the subject.

DOI:

10.14359/17453


Document: 

SP70-20

Date: 

January 1, 1981

Author(s):

Peter B. Lindley

Publication:

Symposium Papers

Volume:

70

Abstract:

Natural rubber bearings containing steel laminates are located between components of a concrete structure to prevent damage to the structure when relative movements occur between the structural components. The stiffnesses of rubber bearings are markedly shape dependent, and stiffness relations enable bearings suitable for particular applications to be designed. Applications include bridge bearings, antivibration mountings for buildings and for the rail tracks of underground railways and, but still under development, foundation bearings for earthquake protection. As these bearings are made by rubber manufacturers a brief discussion of the manufacturing processes and of the engineering properties of natural rubber should be an aid to meaningful dialogue between engineers and rubber technologists.

DOI:

10.14359/17418


Document: 

SP70-17

Date: 

January 1, 1981

Author(s):

D. G. Manning and A. A. Witecki

Publication:

Symposium Papers

Volume:

70

Abstract:

The paper describes the requirements which were developed for deck joints for the Ontario Highway Bridge Design Code. The Code provisions apply to prefabricated joint assemblies which accommodate translation and/or rotation. The basic philosophy of the Code is that the minimum number of joints be used consistent with the need for articulation and drainage of the structure. Sources of movement and loads on deck joints are discussed in detail. Two types of joint are recognized: those which are sealed against penetration by water and open joints in which the flow of surface drainage is permitted. Requirements for each type of joint are given. Requirements for durability, skid resistance, attrition, noise, ease of inspection, maintenance and modification are expressed qualitatively. Requirements for installation, permissible gaps and anchorage are expressed quantitatively. Factors influencing the selection of the type of joint are given.

DOI:

10.14359/17415


Document: 

SP70-15

Date: 

January 1, 1981

Author(s):

Waldemar Koster

Publication:

Symposium Papers

Volume:

70

Abstract:

The Maurer-Normanker, proved now for 15 years of service, and the new designed Robek-Zahnanker have practically the same high level of quality. However, the new designed Robek- Zahnstegfuge showed far the best results in this dynamic load test. The reason is firstly the fact that the anchor system is incorporated into the profile without the need of any welding eliminating the concern for fatigue failure. And secondly, it was obvious during the dynamic tests that the slim section of the upper profile was working like a leaf spring, so only a reduced load went down to the anchoring system. This surprising result with the Robek- Zahnstegfuge of the laboratory tests in 1978 gives an interesting outlook for further design practices.

DOI:

10.14359/17413


Document: 

SP70-01

Date: 

January 1, 1981

Author(s):

Raymond J. Schutz

Publication:

Symposium Papers

Volume:

70

Abstract:

Joints in structures existed since men first constructed a waddle hut or a bark canoe. These joints were subject to movement then as now. Early structures shedded rain at the joints due to overlapping of small elements such as thatch, slate, clapboard or board and batten. Where overlapping was impractical, (such as in a log hut) early builders used sealants of mud, moss, shredded bark, or pine pitch. As man became more skilled, he developed bituminious-based sealants and sealants based on natural drying oils. As buildings became more sophisticated, elements became larger and movement at the joints increased. Field molded elastomeric sealants were developed with performance far exceeding sealants based on natural materials. These were welcomed by the industry as the final solution, however, despite their excellent properties, field performance was quite often disappointing. This paper covers the development of sealant technology based on the study of joint movement and geometry. Understanding of the high strains which can occur in a sealant has resulted in better design and limits for field-molded sealants and has led to the development of compression seals, mechanically locked and modular preformed sealants for joints which are subject to extreme movement.

DOI:

10.14359/17399


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