René Tinawi

• BSc (eng), DIC, MSc (eng), PhD
• Professor Emeritus at Polytechnique Montréal

This paper provides a summary of the damage to bridges in the M-w 8.8 Chile earthquake of 27 February 2010. Lessons from the different types of structural damage observed on concrete and steel bridges are discussed. The important roles played by soil liquefaction, settlement and embankment failures are highlighted. Aspects such as shear failure of...

This paper provides a summary of the damage to industrial facilities in the M-w 8.8 Chile earthquake of 27 February 2010. The types of damage observed include failure of elevated tanks, collapse and cracking of concrete silos, buckling of steel silos, collapse of conveyor systems, failure of steel bins, and failure of anchor rods. Damage to industr...

During severe earthquakes, ductile flexural walls are expected to exhibit inelastic flexural behaviour while other brittle deformation mechanisms, such as shear, should remain elastic. The philosophy of the Canadian seismic provisions for flexural walls is based on the assumption that the force reduction factor is applicable to both flexure and she...

The seismic behaviour of existing bridges in Canada remains an important problem, since most of these structures have been built before modern seismic provisions. Recent earthquakes around the world have demonstrated that such older structures can behave poorly under even a moderate ground excitation. The cost for a systematic evaluation and retrof...

This paper presents a review of the various seismic retrofitting techniques currently being carried out for bridge structures. After evaluating the performance of existing bridges in past earthquakes and their most common modes of failure, a systematic review of bridge retrofit is discussed. It includes the retrofit of foundations, concrete columns...

An earthquake of magnitude ML = 4.3 occurred near Napierville, Quebec, on November 16, 1993. An accelerograph at the liquefaction, storage, and regasification plant of Gaz Metropolitain in Montreal, about 55 km from the epicentre, recorded the ground motion. Although the maximum accelerations and velocities from this event are small, the accelerati...

Observations on damage to concrete structures, due to the 1994 Northridge earthquake, are reported from a Canadian code perspective. Most of the damaged structures were older, nonductile, structures that do not conform to current design and detailing requirements. Concern is expressed about the seismic hazard of older Canadian structures having sim...

Concrete dams located in northern regions are subjected to severe cyclic seasonal temperature variations, which may contribute significantly to the deterioration of the exposed faces and the long-term degradation of strength and stiffness properties. This paper presents a comparative study of thermal protection methods that might be used to improve...

Many concrete dams and other concrete structures in Canada, and throughout the world, are suffering from deteriorations induced by alkali–aggregate reaction (AAR) that impair the durability and serviceability, and might also affect, in the long term, the safety of the installation. Alkali–aggregate reaction produces concrete expansion, and generall...

Examples of failures of concrete bridges during the Kobe earthquake are presented. Types of failures and their probable causes are discussed, and photographs of reinforcement detailing in the failed columns are shown. An example of the reinforcement in a new bridge column under construction at the time of the earthquake, showing modern detailing st...

A brief history of the detailing changes following different Japanese earthquakes is presented. The design steps for reinforced concrete structures, as prescribed in the 1981 Japanese building code, are described. Observations on the damage and the collapse of reinforced concrete structures caused by the 1995 Hyogo-ken Nanbu earthquake are reported...

The mechanical properties of S2- and S3-type sea ice are reviewed. Strength and, in some cases, elastic moduli are presented for short-term loadings. The loadings considered are uniaxial tension and compression and multiaxial compression; annular tests as well as flexural and shear tests were also reported. The parameters that influence the values...

This paper deals with the bearing capacity of sea ice covers taking into consideration the nonhomogeneity of the material, which is primarily due to variations in temperature and salinity across the thickness. The study is limited to the evaluation of short-term loads that would cause cracking in the ice cover. The general method for evaluation of...

Complex frequencies and mode shapes are evaluated and presented for a guyed vertical axis wind turbine to detect any dynamic instability for a given speed of rotation. The equations of motion are developed in the rotating system of axes of the rotor to eliminate the time dependent terms. These equations take into account gyroscopic effects by evalu...

CASTOR is a major project which involves the development and the integration of the software of a computer aided design for hydro projects. Based on a university–industry collaboration, the project involves a number of specialties such as hydraulics, hydrology, reservoir simulation, site characterization, geotechnical engineering, structures, turbi...

This paper presents a mathematical model for the nonlinear dynamic analysis of aerial electric transmission lines subjected to conductor breakage. The model uses existing finite elements and validated numerical techniques available in most commercial programs capable of handling nonlinear dynamic analysis. ADINA is used in this study. In comparison...

The evaluation of the response of an aerial power line section subjected to cable breakage is a complex dynamic problem in which geometric nonlinearities are important. The solution of the equations of motion of the model calls for direct integration methods for which the stability and behavior, in nonlinear situations, are difficult to predict. Se...

The November 25, 1988, Saguenay earthquake prompted a site visit by a team representing the Canadian National Committee on Earthquake Engineering. This paper contains selected ground motion records in the form of acceleration-time histories, obtained from the Geological Survey of Canada, and corresponding response spectra. The horizontal accelerati...

Damage to building structures during the October 17, 1989, Loma Prieta earthquake prompted site visits by the authors. This paper presents examples of damage to buildings constructed with reinforced concrete, steel, masonry, and timber. The observed damage is used to illustrate some of the seismic design clauses in the 1990 National Building Code o...

This paper examines the influence of masonry infill panels on the natural period of vibration of multi-storey frames in relation to seismic load resistance. Simple analytical expressions are presented to evaluate the natural period of these types of structures with varying number of bays and stories. Results obtained with the proposed formulae were...

Damage to buildings and bridges during the October 17, 1989, Loma Prieta earthquake prompted site visits by the authors. This paper first reviews examples of the severe damage and the collapse of bridges in the 1971 San Fernando and 1987 Whittier Narrows earthquakes. The resulting changes to U.S. bridge design codes and the application of different...

This paper presents the results of an experimental program investigating the behavior of a steel frame with masonry infill panels subjected to cyclic loadings. Three types of masonry frequently used were tested. Loads were high enough to crack the infill panels without yielding the steel frame. The effects of the infill panels on the stiffness and...

Examples of structural damage, investigated during a site visit following the April 22, 1991, Costa Rican earthquake, are presented. Some aspects of the seismic zoning and the seismicity of Costa Rica are discussed. Severe damage to schools, residential dwellings, a hospital, hotels, and roadways is reported. Damage and collapse of bridges due to s...

This paper contains selected ground motion records in the form of acceleration-time histories, obtained from the Geological Survey of Canada, and corresponding response spectra. The horizontal acceleration spectrum obtained for Chicoutimi is compared with the design base shear coefficients from the 1980, 1985, and 1990 National Building Codes of Ca...

The purpose of this paper is to provide a summary of the evolution of seismic design in Canada. This paper presents the significant changes to the approach taken in determining seismic hazards and seismic hazard maps, and describes the evolution of the seismic design provisions of the National building code of Canada. The introduction of important...

A post-processing scheme for force and moment resultant determination in finite element (FE) analysis of concrete dams is proposed. Generally, stress integration is performed with algorithms based on the use of FE shape functions. The global problem of determining the resultant forces and moments, on a planar surface, results from the local treatme...

A theoretical model is developed for transient water pressure variations along a tensile seismic concrete crack with known crack wall motion history. Experimental tests are performed to validate the proposed model. Experimental and numerical results show that water can penetrate into new seismic cracks making them partially saturated over a length...

Water pressure variations along concrete cracks with moving walls are investigated experimentally and theoretically. Displacement control tests were conducted to measure water pressure on 0.4 in long concrete cracks during harmonic motion of crack walls. The effects of key parameters including frequency of excitation, minimum and amplitude of crack...

This paper presents the main features and organisation of CADAM, a computer program, freely available, that has been developed for the static and seismic stability evaluations of concrete gravity dams. CADAM is based on the gravity method using rigid body equilibrium and beam theory to perform stress analyses, compute crack lengths, and safety fact...

Expansion joints have been introduced using diamond wire saws in several existing concrete gravity dams to control deformations and release accumulated compressive stresses due to concrete swelling induced by alkali-aggregate reaction (AAR). Slot cuts have also been used to reduce the detrimental effects of cyclic seasonal thermal loading of dams l...

Displacement controlled shear tests on small concrete lift joint specimens with different surface roughnesses reinforced with an unbonded post-tension cable are conducted to study a related joint constitutive model, and to determine the failure mechanisms associated to it. To investigate the applicability of the joint model, shake table tests are c...

The physical processes governing pressure evolution inside concrete cracks due to seismic excitation, and the procedure to measure it in the laboratory as well as typical test results are presented in this paper. Differences in definitions of uplift pressure according to gravity dam safety guidelines and the results of stability evaluation of a typ...

In the weeks following the Kocaeli earthquake small teams of Canadian researchers had the opportunity to visit the heavily damaged regions, primarily the provinces of Koecali (Izmit) and Sakarya (Adapazari). Amongst other observations, information was gathered on the performance during the earthquake of regional lifelines. The visits by the team me...

The 1975 Turkish code provisions are first reviewed to provide the background for design and detailing of structures prior to the earthquake. The performance of reinforced concrete and masonry structures is described indicating many of the deficiencies in design, detailing, and construction execution. The behaviour of precast concrete structures, s...

The purpose of this paper is to present shake table experiments conducted on four 3.3-m-high plain concrete gravity dam models to study their dynamic cracking and sliding responses. The experimental results are then compared with a smeared cracked finite-element simulation using a nonlinear concrete constitutive model based on fracture mechanics. F...

This paper describes an experimental program to induce thermal fracture in notched unreinforced concrete wall specimens subjected to severe cooling thermal gradients. The variations of the compressive and tensile strengths, the elastic modulus, the fracture energy Gf, and the coefficient of thermal expansion of concrete over a temperature range var...

Displacement controlled shear tests on concrete lift joint specimens with different surface preparations are conducted to compare dynamic sliding joint behavior with the static behavior. Experimental results indicate that the coefficient of friction decreases with the increase in normal load, under both static and dynamic shear The shear strength i...

In July 1996 a severe flood occurred in the Saguenay region of Quebec, Canada. A dike ruptured, and several concrete gravity dama and spillways were overtopped, by up to 2 m. The performance of dams during the flood is discussed, with emphasis on the concept of imminent failure flood for existing dams, the resistance to overtopping for concrete dam...

This paper aims to bridge the gap between simple methods of analysis and advanced numerical techniques for the seismic safety evaluation of gravity dams. A progressive methodology is presented, based on five analysis levels with increasing complexity, for modelling the dynamic interaction mechanisms and response of the dam-foundation-reservoir syst...

Many concrete dams throughout the world are suffering from deteriorations induced by alkali-aggregate reaction (AAR) that impair the durability, serviceability, and might also affect, in the long term, the safety of the installation. AAR produces concrete expansion, and generally leads to a loss of strength, stiffness (cracking), and generates unde...

This paper presents damage-mechanics-based models for predicting the nonlinear static response of unreinforced concrete dams. An anisotropic formulation of the damage because of cracking is proposed. It leads to a reasonable finite-element mesh size, Correct convergence of energy dissipation is ensured by using the energy equivalence concept. The p...

This paper discusses the local approach of fracture using damage mechanics concepts to evaluate the seismic response of concrete gravity dams. A constitutive model for plain concrete, subjected to tensile stresses, is presented. The mesh-dependent hardening technique is adopted such that the fracture energy dissipated is not affected by the finite...

The explicit computation of energy balance for structures subjected to seismic excitation is useful to assess the accuracy with which dynamic equilibrium is achieved in each time-step. Examples on the use of the energy balance concept are presented in the first part of this paper for simple inelastic structures excited by various ground motions. It...

A new analytical development of the seismic hydrodynamic pressure inside pre-existing cracks on the upstream face of concrete dams is presented. The finite control volume approach is utilized to derive an expression for the seismic hydrodynamic pressure using the continuity principle and the linear momentum theorem for the fluid inside the crack. T...

The 1990 edition of the National Building Code of Canada (Associate Committee of the National Building Code, National Research Council, Ottawa, 1990) makes a clear distinction between eastern and western Canada in terms of seismic acceleration and velocity zones. While it is well established that ground motions can be amplified significantly throug...

In July 1990, a series of five blasts took place about 200 m from two liquified natural gas (LNG) tanks belonging to Gaz Metropolitain in Montreal, Canada. One of the tanks lost its thermal insulation capacity at the base after the second blast. Massive cracking was discovered in the insulation material (foam glass), which had to be replaced. The r...

The November 25, 1988, Saguenay earthquake (M(L) = 6.0) is the largest seismic event recorded in eastern Canada. The cable-stayed Shipshaw bridge, which crosses the Saguenay river near Jonquiere, Quebec, suffered significant structural damage during the earthquake. One of four anchorage plates connecting the steel box girders to one abutment failed...

An inspection of the cable-stayed Shipshaw bridge near Jonquiere, Quebec, following the 1988 Saguenay earthquake (M(L) = 6.0) revealed the failure of one anchorage plate connecting the steel box girders to one abutment. This paper is the first of two companion papers describing the circumstances of the failure. The static aspects of the problem are...

This paper presents a mathematical model for the nonlinear dynamic analysis of aerial electric transmission lines subjected to conductor breakage. The model uses existing finite elements and validated numerical techniques available in most commercial programs capable of handling nonlinear dynamic analysis. ADINA is used in this study. In comparison...

The dynamic behaviour of the vertical axis wind turbine of the ÉOLE Project is examined using a special purpose program developed for extracting the complex frequencies and mode shapes of the structure. The precise evaluation of the frequencies is an important step in the design process, to detect any dynamic instabilities of the rotor for a given...

The dynamic behavior of the vertical-axis wind turbine of the EOLE Project is examined using a special-purpose program developed for extracting the complex frequencies and mode shapes of the structure. The precise evaluation of the frequencies is an important step in the design process, to detect any dynamic instabilities of the rotor for a given s...

Complex frequencies and mode shapes are evaluated and presented for a guyed vertical-axis wind turbine to detect any dynamic instability for a given speed of rotation. The equations of motion are developed in the rotating system of axes of the rotor to eliminate the time-dependent terms. These equations take into account gyroscopic effects by evalu...

Nonlinear dynamic analyses are performed using ADINA with four idealizations of a smallscale model of a transmission line section subjected to a conductor breakage condition. Results indicate that higher frequency components of the response must be filtered out in order to achieve numerical stability. Accuracy is obtained provided the effect of the...

Two FORTRAN IV subroutines that generate the stiffness, mass and geometric matrices for plate bending and plane stress elements using displacement models are described. The elements can be of either rectangular or triangular shape with anisotropic properties together with a linear variation in thickness. Although such a formulation is straightforwa...