UP-GRADATION OF UNREINFORCED MASONRY INFILL SQUARE REINFORCED CONCRETE FRAME OF FERROCEMENT COVER WITH EXTERNAL PRESTRESSING TO CATER SEISMIC FORCES

2020 ◽  
Vol 14 (6) ◽  
2016 ◽  
Vol 711 ◽  
pp. 982-988
Author(s):  
Alex Brodsky ◽  
David Z. Yankelevsky

Numerous studies have been conducted on the in plane behavior of masonry infill walls to lateral loading simulating earthquake action on buildings. The present study is focused on a problem that has almost not been studied regarding the vertical (opposed to lateral) in-plane action on these walls. This may be of concern when a supporting column of a multi-storey reinforced concrete frame with infill masonry walls undergoes a severe damage due to an extreme loading such as a strong earthquake, car impact or military or terror action in proximity to the column. The loss of the supporting column may cause a fully or partly progressive collapse to a bare reinforced concrete frame, without infill masonry walls. The presence of the infill masonry walls may restrain the process and prevent the development of a progressive collapse. The aim of the present study is to test the in-plane composite action of Reinforced Concrete (RC) frames with infill masonry walls under vertical loading through laboratory experiments and evaluate the contributions of infill masonry walls, in an attempt to examine the infill masonry wall added resistance to the bare frame under these circumstances. Preliminary results of laboratory tests that have been conducted on reinforced concrete infilled frames without a support at their end, under monotonic vertical loading along that column axis will be presented. The observed damages and failure modes under vertical loading are clearly different from the already known failure modes observed in the case of lateral loading.


Bauingenieur ◽  
2018 ◽  
Vol 93 (09) ◽  
pp. 333-341
Author(s):  
C. Butenweg ◽  
M. Marinkovic

Stahlbetonrahmentragwerke mit Mauerwerksausfachungen weisen nach Erdbebenereignissen häufig schwere Schäden auf, da die Ausfachungen ohne weitere konstruktive Maßnahmen mit vollem Kontakt zum Stahlbetonrahmen eingemauert werden. Durch die unplanmäßige Beteiligung am horizontalen Lastabtrag erfahren die Ausfachungen Belastungen in Wandebene und beeinflussen das globale Schwingungsverhalten der Rahmentragwerke. In Kombination mit den gleichzeitig auftretenden seismischen Trägheitskräften senkrecht zur Wand führt dies in vielen Fällen zu einem Versagen der mit niedrigen Festigkeiten ausgeführten Ausfachungen. Dies war der Anlass in dem europäischen Forschungsprojekt INSYSME ein Entkopplungssystem zu entwickeln, mit dem Rahmen und Ausfachung durch ein spezielles Profil aus Elastomeren entkoppelt werden. Das Profil ermöglicht Relativverschiebungen zwischen Rahmen und Ausfachung und stellt gleichzeitig die Aufnahme von Belastungen senkrecht zur Wand sicher. Der Beitrag erläutert zunächst den Aufbau des Systems und gibt einen Überblick über die in Kleinbauteilversuchen ermittelten Tragfähigkeiten. Zudem werden experimentelle Untersuchungen an mit hochwärmedämmenden Mauerziegeln ausgefachten Stahlbetonrahmen mit und ohne Entkopplungssystem für getrennte und kombinierte Belastungen in und senkrecht zur Wandebene vorgestellt. Auf Grundlage einer Versuchsauswertung und eines Ergebnisvergleichs werden Wirkungsweise und Effektivität des entwickelten Entkopplungssystems demonstriert.


2016 ◽  
Vol 32 (4) ◽  
pp. 2337-2355 ◽  
Author(s):  
Laura Redmond ◽  
Lawrence Kahn ◽  
Reginald DesRoches

Reinforced concrete buildings with masonry infill are vulnerable in earthquakes primarily because the masonry walls often fail due to out-of-plane forces and can trigger soft-story collapses. In order to prevent these failures, many engineers in the Caribbean have partially reinforced the infill walls and connected them to the reinforced concrete frame. This forms a hybrid concrete-masonry structure. Hybrid concrete-masonry structures have the potential to improve the seismic performance of many structures across the globe, as they are an easy adaptation from traditional unreinforced masonry infill. However, there is little codified guidance for this type of structure, and the influence of the masonry infill and dowel connections on the in-plane behavior of the frame is often neglected. This paper summarizes the current design and construction practices for hybrid concrete-masonry structures and assesses their seismic performance via cyclic tests on full scale test specimens. Based on the results of the experiment, a method is proposed to account for the dowel connections and the partially reinforced infill when designing hybrid concrete-masonry structures in earthquake zones.


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