The research conducted within CEISCE is priority for public safety and economy. In particular, many of the research projects aim at developing and applying new techniques for the design, assessment,rehabilitation and protection of critical structures against the effects of extreme events (earthquakes, ice cover effects and ice storms, floods, extreme temperatures, winds, collisions and explosions, landslides, etc.). The research within CEISCE can be classified into the main axes described below.
A large number of bridge structures were built before the advent of modern structural design and safety standards. Most of these aging structures have undergone significant deterioration, accelerated by severe climate conditions, particularly in Quebec.
This research axis aims at:
- Determining the vulnerability of bridges to extreme loads generated by earthquakes, vehicle impacts, extreme temperature variations and flooding,
- Evaluate the risks associated with the above-mentioned extreme loads,
- Prioritize bridges for rehabilitation or deployment of post-event inspection teams,
- Develop cost-effective protection and rehabilitation solutions.
Many of the bridges in Quebec have not been designed considering the latest knowledge caraterizing the region's seismic hazard that is typical of eastern North America (ENA). This research theme aims at developing and applying comprehensive strategies for the seismic assessment and rehabilitation of bridge structures, including the determination of seismic vulnerability and deficiencies, risk assessment, damage prediction, the development of cost-effective protection and rehabilitation techniques, and prioritization of associated interventions. Numerical simulation models are developed and validated against laboratory testing of large-scale specimens (e.g. bridge columns, seismic protection systems such as isolators or dampers). The developed methods and obtained results are implemented in innovative seismic performance-based design and evaluation tools, and the proposed solutions are applied in the field to concrete cases.
Reliable tools to assess the vulnerability of bridges to the effects of floods, especially rapid floods, and ad-hoc rehabilitation strategies are lacking in Quebec. The high flows generated by these floods can lead to instability or failure of critical components (piers, abutments, decks), and sometimes to the collapse of the structure. This theme aims at :
- develop numerical simulation models to assess the vulnerability of bridges to flooding;
- develop and perform laboratory test protocols to validate numerical simulations;
- propose anti-flood rehabilitation solutions;
- Apply the proposed methodology to real-life bridge case studies in Quebec. An index of bridge vulnerability to the effects of flooding will be developed for use by municipal and provincial authorities as a tool to help prioritize rehabilitation interventions and prepare emergency evacuation plans.
Vehicle collisions with bridge structures can jeopardize the safety of road users and cause major economic losses due to traffic disruptions. This topic aims to:
- develop reliable numerical models to assess the vulnerability of bridge structures (piers and decks) to vehicle impacts and the associated risks;
- perform laboratory tests on large-scale bridge pier and deck specimens to validate numerical simulations;
- determine the equivalent impact load of a typical Quebec traffic vehicle on a bridge deck, which is key to risk and consequence assessment but is not addressed in current Canadian standards;
- propose and experimentally test anti-collision rehabilitation solutions;
- develop a bridge vulnerability index to prioritize bridges for protection.
When exposed to low temperatures, bridge materials and seismic protection devices (e.g., seismic isolators and dampers) can change their properties from the design temperature, and thus lose their effectiveness, or worse, affect the safe performance of the structure. Floods accompanied by massive drifting ice blocks can intensify the effects of impacts on piers and decks. Therefore, this topic aims to develop:
- thermomechanical coupling models and their experimental validation to assess the vulnerability of bridges to the effects of earthquakes combined with low temperatures;
- an experimental protocol to improve the cyclic tests prescribed by the CSA-S6 standard to qualify seismic protection systems under low temperatures;
- multiphysics simulation models to evaluate the effect of drifting ice blocks during floods on the structural integrity of bridges.
Residential and office buildings in Quebec are exposed to a multitude of hazards that threaten their structural integrity, including earthquakes, wind and snow. This theme aims to pool the complementary expertise of CEISCE researchers to assess the structural vulnerability of this important category of buildings to the hazards studied, and to propose innovative and economical rehabilitation solutions. The design and rehabilitation methods will be developed by studying, numerically and experimentally, not only the deformability and resistance of one structural component at a time (e.g., a critical zone of a wall, a roof), but also the compatibility of the deformations and the redistribution of the forces in the whole building under three-dimensional (3D) solicitations. Specific structural performance and rehabilitation objectives will be related to the anticipated hazard levels in Quebec.
Relatively rigid structures, such as multi-storey buildings with reinforced concrete shear walls, or low-rise steel or masonry buildings, react strongly to earthquakes in Quebec. There are still many uncertainties regarding the design and seismic rehabilitation of these structures. In this theme, CEISCE will continue to carry out large-scale tests of the structural systems identified above on a shaking table or by hybrid specimen-model simulation. We aim to:
- develop numerical models to adequately simulate nonlinear behavior;
- obtain experimental data from large-scale specimens;
- develop cost-effective rehabilitation techniques (e.g. lining with composite materials, energy dissipating bracing, controlled cribbing);
- improve the seismically optimized design and rehabilitation details of these structural systems and document them in guidelines.
The last few years have seen an increasing recurrence of high winds in several regions of Quebec. These winds are critical for the structural integrity of high-rise residential and office buildings, but also those with irregular configurations, regardless of their height. In this theme, CEISCE researchers collaborate to reduce the uncertainties related to wind loads on buildings, and to improve and simplify their calculation according to the National Building Code (this calculation is indeed complex and often inaccurate in the case of irregular buildings. This work is based on experimental results from wind tunnel tests, and on advanced fluid dynamics models that the researchers will develop to take into account wind-building interactions and geometric irregularity. Particular emphasis will be placed on the wind resistance of building exteriors and roofs.
In this axis, CEISCE researchers will continue their work on the development of a vulnerability assessment program for priority buildings in Quebec (e.g. schools, hospitals, fire stations, police stations, emergency shelters) and their rehabilitation in the face of earthquakes, wind and snow. Most of these critical structures must remain functional during and after an extreme event. The research work will lead to decision support tools prioritizing the rehabilitation of sensitive buildings according to their level of vulnerability. An interactive map integrating the results obtained will be produced for Montreal and Quebec City. Practical guides on the optimization of the rehabilitation of priority buildings will be developed and presented during workshops for the benefit of engineers and architects in different regions of Quebec, as well as to the ministries concerned (education, transportation, public safety).
CEISCE will continue to develop a seismic rehabilitation strategy for schools and priority buildings based on the prediction of their performance according to the anticipated seismic hazard level. The prioritization of buildings to be rehabilitated is based on the analysis of data collected on their structural configuration (materials, geometry) and seismic microzonation. More than one hundred schools in the Montreal area, central Quebec, and the Eastern Townships have already been evaluated. A large-scale experimental program will be pursued to better characterize the behaviour of low- to mid-rise buildings by performing seismic tests on different structural components (e.g. non-ductile frames and masonry or reinforced concrete walls). The results of these tests will be used to validate more accurate numerical models to assess the seismic vulnerability of prioritized buildings and optimize appropriate retrofits.
Schools and hospitals often have irregular structural configurations, which can make them vulnerable to wind effects. This particular issue is addressed by this research, which is related to Theme 2.2. Experimental and numerical evaluation of wind pressures on irregularly shaped buildings will be continued to provide recommendations for the sustainable design and rehabilitation of schools and hospitals in the face of wind. A series of wind tunnel tests for a number of configurations is planned to identify trends and establish the extent to which current standards are valid for the irregular shapes tested. Particular attention will be devoted to the effects of wind-induced torsion, a critical behavior that is still poorly understood. CEISCE will also address the vulnerability of priority building roofs to wind effects and their economical and sustainable rehabilitation.
The cost of the 1998 ice storm in Quebec is estimated at nearly $3 billion. The storm is best remembered for the chain of collapses of power line towers. What is less well known is that during the ice storm, the ultimate strength of the roofs of many schools and arenas used as shelters was nearly reached due to increased snow and rain loads. Some collapses and damage to critical shelters were even observed. The main objective of this research topic is to re-evaluate the loads and safety factors currently prescribed in the National Building Code for exceptional snow and ice loads calculations.
Low-rise steel industrial buildings (LSIBs) with metal roofs make up a large portion of commercial buildings in North America. They include the majority of commercial buildings, factories, warehouses, shopping malls, water treatment centers, mine headframes, etc. of 1 to 3 stories. The recent IPCC report (2018) indicated that they are the category with the highest economic losses in the event of extreme events, such as winds or earthquakes.
In this research axis, researchers will aim to develop innovative design methods (analysis of the structural causes of damage, modification of codes and development of control systems) to reduce the impacts of winds and earthquakes on LSIBs. They will also study, experimentally and numerically, the effects of cold on the resilience of these structures, which are still very poorly understood and which particularly affect Quebec with its harsh winters.
The resistance of these structures to wind- and earthquake-induced dynamic lateral loads depends on the diaphragm effect of the roof, and there is currently very little information on their dynamic behavior. This CEISCE theme focuses on characterizing the dynamic properties of LSIBs. The work will include dynamic tests on several LSIBs built in Quebec to improve the prediction of seismic loads according to the National Building Code and to validate numerical models. Extensive numerical simulations will then be performed to develop design rules that reflect the behaviour of BAFHs, including the effects of roof diaphragm flexibility. This work will lead to more economical buildings while optimizing their resistance to dynamic loads.
In Quebec, it is important to design and evaluate the seismic behaviour of structures taking into account low temperatures. In this theme, researchers are studying the ductility of steel components of industrial buildings under very low temperature seismic loads. Limited previous studies suggest that cold temperatures can significantly affect the ductility of steel components. A program of several types of tests on steel specimens subjected to very low temperatures will be conducted. Also, the operation of seismic protection equipment (isolators and dampers) may be affected by low temperatures. The adaptation of these equipments to severe climatic conditions must be validated to ensure adequate performance levels. Static and dynamic tests to characterize the seismic behavior of structures with different seismic isolation systems will be performed.
Hydraulic structures are of major social and economic importance in Quebec. The Dam Safety Act, which came into force in 2002 following the Saguenay floods (1996), requires the owners of these structures to regularly evaluate their safety performance, particularly under the effect of earthquakes and floods.
This line of research aims to consolidate the great expertise they have developed in this field, addressing the persistent deficiencies in the process of reliable assessment of the safety of dams and related structures and their rehabilitation. To this end, state-of-the-art tools and guidelines will be developed based on:
- a wide range of numerical methods adapted to the needs of the engineer;
- laboratory testing of critical component specimens;
- data collected directly on dam sites (e.g. in situ dynamic tests, LiDAR).
This research theme focuses on the seismic evaluation and rehabilitation of dams and related critical structures (e.g., gate towers, spillways). In particular, the objectives are to:
- improve and standardize seismic evaluations of dams, by developing advanced simulation models (finite or discrete elements) taking into account dam-reservoir-foundation interactions, concrete cracking, slip at joints, hydromechanical couplings, 3D effects, and various energy dissipation mechanisms;
- develop rehabilitation techniques (e.g. steel reinforcement or post-tensioning cables);
- develop and apply innovative testing protocols (e.g., vibration table or hybrid specimen-model simulation) on specimens of critical dam components and related structures to validate numerical models and evaluate the performance of proposed rehabilitation techniques.
Pressure fields and forces associated with water flows submerging concrete dams are traditionally determined using simplified or empirical methods, which may neglect the effects of 3D geometric irregularities, fluid-structure interaction and the presence of debris or ice blocks. The objectives of this theme are:
- to develop advanced numerical simulation tools (e.g. 'CFD' volume elements, 'SPH' meshless particles) adapted to the study of submerged dams and taking into account the above mentioned parameters;
- to perform model-to-model (efficiency, performance and accuracy) and/or model-to-experiment validations of the developed simulations;
- to couple the hydrodynamic analyses with those of the structural stability of the dams in order to evaluate their factors of safety in case of flooding;
- to develop rehabilitation techniques to reduce the vulnerability of dams to flooding.
Overhead power lines and transformer stations are essential infrastructure in Quebec, especially during and after an extreme event.
This line of research aims to develop state-of-the-art design and evaluation techniques for these strategic structures, taking into account the extreme conditions to which they are exposed: extreme ice, combined wind and ice, synoptic or local windstorms (tornadoes and downbursts), component failures (accidental or vandalism), cable instabilities (vortex detachment and galloping vibrations), and seismic acceleration.
This work is based on:
- a probabilistic assessment of the climatic and seismic hazard;
- advanced numerical models of the complex behavior of cable, support and/or substation systems;
- in situ and laboratory tests by hybrid specimen-model simulation.
The reliability and safety of the electric transmission system requires a better understanding of the effects of wind, ice and earthquakes on the system, and an improvement of the computational methods in terms of accuracy and efficiency. In this theme, CEISCE researchers are pursuing the development and application of new advanced methods for numerical simulation of the behavior of critical components (e.g. lattice towers, cables, conductors, connections, foundations, substation structures). Different numerical approaches (e.g. finite element, volume element 'CFD', meshless particle 'SPH') will be introduced, applied to real cases and compared (efficiency, performance, and accuracy). The data implemented in the models will be collected in situ (e.g. by ambient vibrations). Innovative solutions to mitigate the effects of the above-mentioned loads (e.g. dampers, anti-ice accumulation spirals) will be developed and/or tested.
Component failures can cause failure mechanisms, sometimes in cascade, affecting the reliability of a large portion of the network. For example, the breakage of a conductor generates a dynamic impulse that can propagate from support to support, thus leading to chain failures. In this theme, CEISCE researchers will develop original numerical models to, first, simulate and better understand the dynamics of component failures (including material non-linearities, a parameter neglected in current models), and then limit the consequences of these failures by introducing energy dissipators and/or ductile rather than resistant supports (e.g. anti-cascade towers). The proposed numerical models and protection techniques will be validated by innovative laboratory tests based on specimen-model simulation.
Landslides due to gravity instability, caused directly or not by earthquakes, can trigger the movement of large volumes of soil, and threaten the structural integrity of structures over a large area. The underground structures of drinking water and electricity distribution networks, which have a neuralgic role in society, are also vulnerable to earthquakes. Despite their simplicity, current seismic evaluation methods have several limitations (e.g., little or no consideration of dynamic amplifications, 3D effects, damping, and shear strength).
This research axis aims at developing new methods for the stability analysis of slopes, embankments and underground structures. Several approaches will be adopted, ranging from simplified methods to advanced simulations of site responses (e.g. soft soils in Quebec) including state-of-the-art constitutive models.
In this research theme, CEISCE aims at proposing efficient and effective tools to analyze ground motion, slope or embankment stability, site effects, and soil behavior under extreme vibratory loading related to earthquakes and construction activities. One approach will be to isolate the effects of the most influential parameters in this type of analysis (e.g., natural period of deposition, seismic amplification, frequency content), and to integrate them into new practical methods for engineers. CEISCE researchers will continue their work on the analysis of the liquefaction potential of soils in case of earthquake and the consequences on structures. The proposed constitutive laws and numerical simulations will be validated by laboratory tests on reduced soil specimens (e.g. material characterization, seismic simulator and shaking table).
This theme focuses on the seismic vulnerability of underground drinking water or electricity distribution networks (UWEDN). The impact of earthquakes on water supply is not well documented in Quebec. The same observation applies to the buried electricity distribution network. The objective of this theme is to fill these gaps. CEISCE researchers will collaborate to develop numerical simulations to quantify and compare the risks of damage and/or failure of the UWEDN during an earthquake. Particular attention will be dedicated to:
- factors influencing the likelihood of failure of a UWEDN;
- the potential consequences of disruptions (individual or occurring in sequence) on the supply of drinking water and electricity and their prioritization. Several scenarios will be studied using a probabilistic approach (i.e. Monte Carlo simulations). The methodology will be illustrated by applying it to the Montreal region's UWEDN.