Experimental and analytical investigation of seismic stability of masonry walls at Beauharnois powerhouse

Abstract

The seismic stability of the facade brick-masonry walls of the machinery building of the Beauharnois powerhouse near Montreal, Quebec, Canada were investigated numerically by use of non-linear models and applying experimental methods on site and on the IZIIS' seismic shake-table. The dynamic properties of the machinery building were obtained by ambient vibration measurements. Based on these results, a model of a representative part of the building, consisting of steel frames and brick masonry wall, was designed and constructed to the reduced scale at the IZIIS' Dynamic Testing Laboratory and then tested on the two-component shake-table. The geometry of the original structure was completely scaled to 1/3, consisting of many realistically simulated details such us: brick layers, steel columns, openings, window frames, steel connectors between brick layers, number of layers, brick dimensions, etc. The material used for the model was: original steel for the frame structure and bricks of reduced mechanical properties for the masonry wall, close to the similitude requirements according to the Backingham's theorem, valuable for adequate artificial-mass simulation model as well as true replica simulation model. More than 50 seismic tests were performed considering the design earthquake Nahanni NWT, H1, with a time scaling factor of 3 1/2 , and acceleration scaling factor 1, according to the model design rules. The intensity of the applied input earthquake excitation was from 0.05 to 1.2 g. The design peak acceleration of Nahanni earthquake was 0.2 g. The cracks development was stated at 0.7 g input acceleration. These were concentrated around the openings. No collapse happened even under the strongest earthquake input. The numerical part of this paper deals with formulation/application of the critical plane approach to seismic analysis of masonry structures. Starting with the constituents, i.e. mortar and bricks, the macroscopic strength properties of masonry were established based on numerical homogenization. Generally, based on all the performed experimental 123 422 Bull Earthquake Eng (2010) 8:421-450 tests, considering some simplifications and assumptions in the constructing details, as well as in the design of the model, the global conclusion is that the existing wall is very well incorporated in the steel structure of the powerhouse. The complementary stiffness of the steel frame and the brick masonry wall produces interactive deformation of the system. Only local cracking and relative displacement between the wall and the steel frames could be expected in the case of a strong earthquake.

Fixed and base isolation retrofitting of historic masonry buildings

“…Based on the damage suffered by historic buildings in response to seismic loading (Tema-Colunga et al, 1992;Brunea et al, 1994;Oliveira, 2003), in conjunction with experimental laboratory investigations of models of non-reinforced masonry buildings (Tomazevic, 2005;Sheppart and Tomazevic, 1986;Krstevska et al, 2010), the following types of earthquake damage characteristically occur in historic buildings: In some cases, collapse of the floor or the roof may take place. During slight to moderate ground motion, the structure often behaves as a single unit and the only observable damage may be small cracks in the walls.…”

Restoration and Strengthening of Historical Buildings: The Example of Minceta Fortress in Dubrovnik

“…Various numerical techniques and models with different complexities and accuracies for the static and dynamic analysis of masonry structures are presented [1][2][3][4][5][6][7][8][9][10][11]. Different methodologies for the structural restoration of historical buildings are described [12][13][14][15]. e acquired experience on the analysis and strengthening of numerous buildings in Italy after the recent earthquakes were also useful for this study [16][17][18][19][20].…”

A Review of Ambient Vibration Technique on Bridges

“…Ambient vibrationtest widely applied to different types of bridges such as a double-deck bridge [6], pre-stressed concrete box girder bridge [2,4], continuous girder bridge [12], reinforced concrete bridge [16], cable stayed bridge [12] and stone masonrybridge [9] in orderto determine the dynamic characteristics of the bridge. It is desirable to measure the dynamic characteristicsfor both newly constructed bridge and for the existing bridge, it in term of natural frequencies, mode shape and modal damping of the bridge to understand better their dynamic behavior under normal traffic loads an also during extreme loads such as those caused by seismic events or high wind [4].…”