Building code | EPFL Graph Search

A building code (also building control or building regulations) is a set of rules that specify the standards for constructed objects such as buildings and non-building structures. Buildings must conform to the code to obtain planning permission, usually from a local council. The main purpose of building codes is to protect public health, safety and general welfare as they relate to the construction and occupancy of buildings and structuresfor example, the building codes in many countries require engineers to consider the effects of soil liquefaction in the design of new buildings. The building code becomes law of a particular jurisdiction when formally enacted by the appropriate governmental or private authority. Building codes are generally intended to be applied by architects, engineers, interior designers, constructors and regulators but are also used for various purposes by safety inspectors, environmental scientists, real estate developers, subcontra

Seismic vulnerability of cultural heritage buildings in Switzerland

Mylène Devaux Baudraz

Seismic risk for cultural heritage buildings has been underestimated for years in Switzerland. A strong earthquake can occur at any time in this region, as it has been shown during the last centuries. As reminder the 1356 seismic event that destroyed the city of Basel can be quoted; this event, whose intensity is assessed as having been I=IX on the European Macroseismic Scale (EMS-98), is recorded as the most violent earthquake that struck central and northern Europe. Since 2003 or even 1989, the seismic safety of common buildings is well defined through modern building codes (Swisscodes (SIA)). However, this is not the case of cultural heritage buildings whose seismic vulnerability has been only partly addressed. This PhD thesis was initiated in order to fill in this void of knowledge by creating a methodology for assessing the seismic vulnerability of historical edifices. Surveys carried out on cultural heritage buildings after seismic event showed that such kind of structures are particularly vulnerable under seismic actions. This vulnerability is essentially due to their particular structure that is characterized by slender components (pillars), wide open spaces, quite big masses located at high levels (vaults and their filling, lantern towers, etc.) on one hand; on the other hand, they generally have few components that can resist the lateral actions perpendicular to the nave and their masonry fabric is non-ductile. Moreover the non-existence of a stiff horizontal component (or a deformable one in case of wooden ceilings) and heavy masses concentrated in walls rather at floors make it impossible to apply models that have been developed for common buildings. The methodology that is presented in this report is composed of four steps. It gives the possibility to first sort out the sacred edifices that are seismically vulnerable from the ones that are not vulnerable. The second step allows engineers to determine the seismic vulnerability of a given edifice by the use of simplified models that give valuable results. In case more accurate results are required, more sophisticated models can be applied, as the Finite Element Method. In the last step, the seismic vulnerability of the edifice is put in parallel with the expected peak ground acceleration of the region. This last phase permits to set if the given edifice can be damaged by earthquakes, which damage is expected and which retrofitting is required.

EPFL2008

Fire performance evaluation of GFRP-balsa sandwich bridge decks

Niloufar Vahedi

Bridges are a critical component of national infrastructures and economies. A significant percentage of bridges built all around the world are made of reinforced concrete which according to building codes have a life span between 80-100 years. However, structural inspections demonstrate that deterioration can begin in as little as 10 years due to the limited durability of steel-reinforced concrete. Exposure to humidity, freeze-thaw cycles and de-icing salts during winter result in corrosion of the steel reinforcement and spalling of the surface concrete which subsequently lead to partial or full bridge closure for required repair. Maintenance, upgrading and replacement of bridges may have significant economic and social impact due to disturbances in traffic flow. Mentioned reasons motivated scientists and engineers to develop and use more durable alternative materials with lower life-cycle cost. Composite sandwich bridge decks composed of glass fiber-reinforced (GFRP) face sheets and a balsa wood core, which are subject of this projects, provide the possibility of a more durable, lightweight and easily installed alternative. Balsa wood is a lightweight wood species exhibiting high strength- and stiffness-to-weight ratios, and therefore it is a favorable core material in bridge decks. However, this new type of sandwich bridge decks has to meet the same requirements as traditional concrete decks do. In particular, their behavior during a fire incident has to be known and predictable. Although fire is an accidental action according to Eurocodes, it has to be taken into account in the design of bridges and should not lead to a premature collapse. The knowledge about the combined thermo-mechanical behavior during a fire of these new sandwich decks is therefore crucial, in particular since the polymer matrix of the GFRP material and the balsa core are sensitive to high temperatures and combustible.GFRP sandwich structures are also used in other high-risk fire applications, e.g. in the automotive, naval and aerospace fields and numerous works about their thermo-mechanical behavior have been performed. However, these results cannot be simply transferred to GFRP-balsa sandwich bridge decks which are subjected to much more severe loads and their life span is much longer. The aim of this project is thus to investigate the thermo-mechanical behavior of GFRP-Balsa sandwich bridge decks in order to overcome this barrier of insufficient knowledge.Three level of investigations are planned, a) on the constituent material level, b) on the sandwich panel level, and c) on the bridge deck and superstructure level. Experimental investigations and modeling are conducted on each level from small- to full-scale. Since the performance of GFRP laminates under elevated temperatures have been investigated by many researchers, only thermo-physical and thermo-mechanical properties of balsa wood are investigated by proper experiments. At the second level, thermo-mechanical sandwich response models are developed and validated by experiments. The final level is conducted in order to investigate the thermo-mechanical behavior of the bridge deck at the structural system level which includes adhesively-bonded joints between the individual balsa panels of the deck and between the deck and the bridge girders. Furthermore, post-fire recovery models are established in order to assess the remaining structural capacity after a fire incident.

EPFL2022

Considering snow depositions and transport mechanisms in meteorological analysis of predicting snow loads on buildings

Michael Lehning, Borui Zhang, Qingwen Zhang

The meteorological conditions determine snow evolutions on and around buildings. Those climatic impacts have been independently considered in the current design codes of buildings, namely the wind pressure and the snow load. But snow load estimates are only based on precipitation assessments without considering the joint effect of wind and snow precipitation which lead to wind dominated deposition and snow transport. Thus, the statisticsbased data provided by those building codes seem practically inadequate or at least incomplete. Using the data provided by upper-air and ground meteorological stations in northern China, including snowfall, wind velocity, and temperature, as indicators, we propose a series of statistical relationships covering aspects of snow precipitation and snow drifting. For those meteorological indicators that can affect building snow evolutions, more detailed analyses on their spatial and temporal changes have been achieved. The regionalization of snow precipitation features in northern China has also been proposed based on the clustering analysis on meteorological joint effects. The result shows that the snowfall in most northern regions of China is generally not heavy and in the form of a uniform deposition. The wind dominated depositions around buildings are more likely to appear in the regions around the Bohai Sea.

ELSEVIER2022