Strengthening of existing structures

These guidelines are now a constituent part of the technical regulations for constructions (Ministerial Decree, January 14th 2008), providing clear instructions for designers and technicians on the use of fiber-reinforced materials in the strengthening of existing structures. 

Concrete Under Earthquake Excitations Concrete is widely used in retrofit and strengthening of existing structures. Recent developments in cement-based materials are aiming at... 

Recent Advances in Metal-Based Materials The use of shape-memory alloy (SMA) reinforcements is very promising in retrofit and strengthening of existing structures. SMAs have more than one crystal structure. This is called polymorphism. The prevailing crystal structure or phase in polycrystalline metals depends on both temperature and external stress. They are a class of metallic alloys that can remember their initial geometry during transformations (forward and reverse) between two main phases at their atomic level (austenite and martensite). 

Fibre reinforced polymer (FRP) composite materials for strengthening of existing masonry structures... 

Rehabihtation systems involving structural adhesives have been used for many years in on-site repair and strengthening of timber structures. However, because they exhibit excellent initial joint strength when tested in standard climate conditions, there has not been a major concern about their service durability and reliable and reahstic accelerated ageing tests do not, therefore, currently exist [20]. 

The purpose of the above is to specify requirements for a cold-cure adhesive to permit either the repair or strengthening of existing concrete structures by bonding on additional external steel plate reinforcement, or the construction of steel/concrete composite units in which wet concrete is poured on to steel freshly coated with a layer of adhesive. In both cases the adhesive serves to resist the interfacial shear stresses necessary to ensure structural composite action between the steel and concrete. For these purposes a cold-cure adhesive is defined as one which is capable of curing to the required strength between the temperatures of 10 °C and 30 °C. 

Presented further herein are parts of the results from the static and dynamic analyses performed according to the procedure described in Sect. 8.3, as well as the characteristic details of repair and strengthening of the structural system and consolidation of the existing foundations and walls. 

Taijsten, B. (2002), FRP strengthening of existing concrete structures —design guidelines , Lulei University Printing Office, Lulea, Sweden. 

In other words, the result of a project quality plan is adequate project quality documentation. This includes procedures and instructions developed mainly for the given project. It is apparent that in the following subsections, only reference to the project quality plan and its documentation will be made, since the company quality system is beyond the scope of this entry. At the same time, an effort will be made to adapt the general mles in effect mainly for new structures to seismic retrofitting and strengthening of existing buildings and public works. 

It is important to keep in mind that added materials for repair or strengthening are submitted to quite different loading histories than those applied to the materials of existing structural elements. This fact should be correctly taken into account during the pertinent redesign. 

This entry presents basic principles, criteria, and procedures in regard to the conceptual design of seismic strengthening of existing ordinary structures and its treatment in current codes. In this context, certain code provisions constitute a significant part of the present entry. 

Interventions to individual structural members or to parts of an existing masonry structure should be part of a global intervention strategy. The selection of a strategy and, hence, of appropriate intervention techniques (for the repair or strengthening of a structure) is based on a series of investigations and studies that should precede the redesign of the stmcture, as briefly described herein ... 

Strengthening of the connections is often the most cost effective upgrade for existing buildings if it does not require removal of existing interior walls and equipment. For a member to absorb blast energy and be structurally efficient, it must develop its full plastic flexural capacity. This requires a substantial increase in shear capacity at the connections to avoid failure. 

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