The effectiveness of anovel Post-Tensioned Metal Strapping(PTMS)techniqueat enhancingthe seismic behaviourof asubstandard RC buildingwas investigated through full-scale shake-tabletests duringthe EU-fundedproject BANDIT.The building had inadequate reinforcement detailing in columns and joints toreplicateold construction practices.After thebarebuildingwas initially damagedsignificantly,itwas repairedand strengthened with PTMS to perform additionalseismic tests.The PTMS technique improvedconsiderablythe seismic performance of the tested building.Whilst the bare building experienced critical damageatan earthquake of PGA=0.15g, thePTMSstrengthened building sustained a PGA=0.35gearthquake without compromising stability.

Steel liquid storage tanks are widely used in industries and nuclear power plants. Damage in tanks may cause a loss of containment, which could result in serious economic and environmental consequences. For the purpose of the earthquake-resistant design of tanks, it is important to use a rational and reliable nonlinear dynamic analysis procedure. The analysis procedure should be capable of evaluating not only the comprehensive seismic responses but also the damage states of tank components under artificial or real earthquakes. The present paper deals with the nonlinear finite element modeling of steel liquid storage tanks subjected to seismic loadings. A reduce-scale unanchored steel liquid storage tank with the broad configuration from a shaking stable test (i.e., the INDUSE-2-safety project) is selected for this study. The fluid-structure interaction problem of the tank-liquid system is analyzed using the Abaqus software with an explicit time integration approach. In particular, the steel tank is modeled based on a Lagrangian formulation, while an Arbitrary Lagrangian-Eulerian adaptive mesh is used in the liquid domain to permit large deformations of the free surface sloshing. The finite element results in terms of the sloshing of the liquid free surface and the uplift response of the base plate are evaluated and compared with the experimental data that is obtained from the shaking table test for the tank under the INDUSE-2-safety project.

test, which induces a near uniaxial loading, were proposed and developed to reach higher biaxiality ratios (ratio between mechanical quantities in axial and in circumferential direction). The first optimization, named HB-EDC for High-Biaxiality EDC, allowed to reach transverse plane strain conditions. The second optimization, named VHB-EDC for Very High Biaxiality EDC, was designed to reach higher loading biaxiality ratios. These optimized EDC tests were performed * Tel.: +33 1 69 08 39 43; e-mail: arthur.hellouin-de-menibus@cea.fr 1 at 25 • C, 350 • C and 480 • C on unirradiated hydrided Cold Worked Stress Relieved (CWSR) Zircaloy-4 samples. First, samples unhydrided or uniformly hydrided up to 1130 wppm were tested. Secondly, samples hydrided at 310 wppm with a hydride blister were tested. A large ductility reduction is induced by the increase in biaxiality level in absence of a hydride blister or with small blisters (<50 µm deep). The fracture strain decreases quickly with the blister depth at 25 • C, but more progressively at higher temperature. An equation that quantifies the fracture strain reduction with the blister depth is proposed. Eventually, one of the tests developed in the present study, the HB-EDC test, was proven to be a good compromise between the test complexity and the stress state reached. It is a good candidate to characterize the mechanical behaviour of irradiated cladding.

This paper describes an experimental investigation into the seismic response of concentrically braced steel frames (CBFs). Twelve shake table tests were performed on full-scale single storey frames, each containing a pair of identical brace members. The experimental programme examined the behaviour of brace members with four different square and rectangular hollow cross-sections and a range of gusset plate connection details. The aim of the experimental study was to determine the influence of brace and gusset plate properties on CBF response from serviceability to ultimate limit states, including collapse. Consequently, all test frames were subjected to three levels of seismic excitation: (i) low-level excitation to examine elastic frame response, (ii) medium-level excitation to examine brace buckling and yielding effects, and (iii) high-level excitation to induce brace fracture. A detailed set of data on the seismic response of CBFs with realistic brace members and connections were obtained from the tests. The experiments were conducted under representative dynamic response conditions as opposed to the conventional idealised quasi-static loading procedures employed in previous experimental investigations of CBF behaviour. The results faithfully capture the behaviour of brace-gusset plate test specimens with different non-dimensional brace slenderness, brace cross-section slenderness, connection types and gusset plate detailing. The response variables measured in each test included the shaking table and frame accelerations and displacements, brace elongation and axial force, and brace member and gusset plate strains. The experimental observations include elastic frame vibration properties, acceleration and drift demands, ultimate failure modes and ductility capacity. The brace-gusset plate test specimens remained elastic at low-level excitations, brace buckling and yielding occurred in all medium-level excitation tests, while specimens exhibited brace fracture under high-level excitation. Fracture did not occur in the gusset plate connections irrespective of whether these were designed using a conventional design method with a Standard Linear Clearance (SLC), or a balanced design with an Elliptical Clearance (EC). However, the balanced design approach showed more uniform distribution of plastic strains and led to higher brace ductility capacities when compared to the conventional design method. Based on the test results, available methods for predicting the ductility of bracing members are compared and assessed, and a number of considerations for design are highlighted and discussed

Abstract. This paper presents the experimental campaign carried out on cylindrical liquid storage steel tank specimens in CEA TAMARIS facility.Two geometries of tanks have been tested on a shaking table under seismic conditions. The broad tank specimen (diameter 3 m, height 0.9 m) was dedicated to the study of sloshing and potential uplifting during the seism. This specimen was unanchored on the table and free to lift or slide. The influence of a floating roof on sloshing has been studied. The slender specimen (diameter 2 m, height 5 m) was dedicated to the foot buckling of the cylindrical shell. The slender specimen was anchored to the table. All the specimens were water filled.All these specimens were strongly instrumented with inner pressure sensors and wave gauges and outer accelerometers and displacement sensors. In addition a new 3D scanner has been used to detect any residual deformation of the tanks by after / before tests comparisons. The purpose was to give to the calculating teams all the needed measurements and information to check their models.Results acquired on one broad tank and one slender tank are presented here.

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To enhance the assessment of reactor pressure vessel life under severe accident, a cooperative research program is conducted between CEA, EDF, and Framatome, parts of which are supported by the European Commission. Within the framework of this program, a model based on Lemaitre and Chaboche with predictive capability in the field of viscoplastic flow, material damage, and failure has been generalized and implemented in CASTEM 2000 finite element code. In order to validate the model in mechanical situations featuring the same basic characteristics as the severe accident scenarios, analytical experiments are conducted on the RUPTHER facility: a thin shell tube is loaded with an internal pressure and submitted to an axial thermal gradient with elevated temperatures. The specific question of the interest of the coupled damage approach in the failure prediction is addressed. Comparisons of the predictions relying on coupled and uncoupled damage-viscoplasticity models show that, at higher temperatures, failure could be predicted through uncoupled damage evaluation provided the main nonlinear effects like large displacements and updated pressure are taken into account, while at lower temperatures coupling between damage and deformation is necessary. Examples based on some RUPTHER creep test predictions are given.