Name: how buildings handle structural movement
Uploaded: 2024-09-12T16:16:29.000Z
Duration: 1 min 27 s
Channel: JoVE

De légers mouvements dans les bâtiments peuvent se produire lors de l’expansion des unités de construction exposées à l’humidité ou du soulèvement des fondations lorsque l’eau du sol se dilate pendant le gel.
Des mouvements peuvent former des fissures dans le bâtiment ; des joints de mouvement tels que des joints de travail, des joints d’enceinte de structure, des joints de séparation de surface et des joints de séparation de bâtiment sont prévus pour éviter cela.
Les joints de travail sont utilisés dans les toits en bardeaux, où de petites bandes sont assemblées selon un motif de chevauchement, tolérant de légers mouvements sans aucune détresse.
Dans un mur creux, le joint souple prévu sous l’angle de l’étagère soutenant le côté extérieur non structurel est un exemple de joint d’enceinte de structure.
Les joints de séparation de surface comprennent les joints d’isolation, les joints de dilatation et les joints de contrôle.
Lorsque de nouveaux ajouts sont apportés à un bâtiment existant, des joints d’isolation sont prévus, permettant le déplacement des nouveaux matériaux sans affecter le bâtiment existant.
Les joints de dilatation sont des fentes ouvertes conçues pour permettre l’expansion des matériaux de construction, tandis que les joints de contrôle sont des lignes de faiblesse créées où des fissures peuvent se produire lorsque les matériaux de construction rétrécissent.
Enfin, les joints de séparation des bâtiments subdivisent les structures complexes en segments discrets qui peuvent être indépendants des mouvements des autres.

joints de mouvement dans les bâtiments

Les joints de mouvement dans les bâtiments sont des éléments de conception essentiels qui s'adaptent aux mouvements inévitables causés par divers facteurs tels que les changements de température, les variations de teneur en humidité et les déformations structurelles. Ces mouvements, s'ils ne sont pas pris en compte lors de la conception et de la construction, peuvent entraîner des dommages inesthétiques ou dangereux. Les joints de mouvement sont intégrés sous différentes formes pour gérer ces contraintes et permettre aux matériaux de bouger sans causer de dommages.

Le type de joint de mouvement le plus simple, les joints de travail, est intégré pendant le processus de construction. Les exemples incluent les toits en bardeaux et les parements en bois biseautés, qui permettent les mouvements thermiques et d'humidité. Les joints de structure/d'enceinte séparent les éléments structurels des éléments non structurels pour empêcher le transfert de charge qui pourrait causer des dommages, tels que les pistes de déflexion dans les murs à ossature métallique ou les joints souples sous les cornières d'étagères supportant les placages de maçonnerie.

Les joints d'isolation sont utilisés pour éviter les interférences entre les matériaux qui doivent se déplacer indépendamment, ce qui est typique dans les rénovations ou lorsque les dalles de béton rencontrent des éléments structurels. Les joints de contrôle créent des lignes de faiblesse prédéterminées pour diriger les fissures de manière contrôlée, ce qui est couramment observé dans les trottoirs en béton et les murs en plâtre. Les joints de dilatation permettent de s'adapter à la dilatation et à la contraction des matériaux, comme c'est le cas dans les murs en briques et les systèmes de murs-rideaux.

Enfin, les joints de séparation des bâtiments divisent les structures complexes en segments qui se déplacent indépendamment, classés en joints de changement de volume, joints de tassement et joints de séparation sismique, chacun répondant à des défis spécifiques en matière de mouvement structurel.

Joints de mouvement dans les bâtiments

De légers mouvements dans les bâtiments peuvent se produire lors de l’expansion des unités de bâtiment exposées à l’humidité ou du soulèvement des fondations lorsque l’eau ...

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Movement Joints in Buildings

how buildings handle structural movement

Buildings are designed to handle movement from temperature changes, moisture changes, and structural deflection. If these changes are ignored, they can cause visible damage or even unsafe conditions. Movement joints give building materials room to move without creating distress.

Working joints are the simplest type. They are placed during construction and help materials cope with change as the building goes up. Shingled roofs and wood bevel siding are common examples because they can move with thermal and moisture changes.

Some joints separate parts of the building so loads do not transfer where damage could happen. These are structure/enclosure joints. In metal-framed walls, deflection tracks help with this kind of movement. Soft joints under shelf angles that support masonry veneer also reduce stress between structural and nonstructural parts.

Isolation joints keep materials that need to move on their own from interfering with each other. They are often used in renovations or where a concrete slab meets a structural element. Control joints work differently. They create a planned line of weakness so cracking happens in a controlled way, such as in concrete sidewalks and plaster walls.

Expansion joints allow building materials to expand and contract. They are often seen in brick walls and curtain wall systems. Building separation joints divide a large structure into sections that can move independently. These include volume-change joints, settlement joints, and seismic separation joints, which each address a different kind of movement problem.

How Buildings Handle Structural Movement

composite masonry walls

Bonding and Materials in Composite Masonry

Composite masonry walls use two or more wythes, or vertical layers, of masonry to form one unified wall. The wythes may use the same material or different masonry materials. They are joined to work together as a single structure. These wythes can be bonded in several ways. Builders may use mortar-filled collar joints, grouted spaces, or rigid metal ties with reinforcement. Masonry header units can also connect the layers, but this method is rare. Metal ties are often preferred because they...

masonry cavity walls

Masonry Cavity Walls and Moisture Control

Masonry cavity walls use two wythes, or layers, with a hollow space between them. The outer and inner wythes are linked only by corrosion-resistant metal ties. This design helps manage water and improve wall performance. When rainwater passes through the outer wythe, it moves down through the cavity. Flashing catches the water and directs it toward weep holes, where it can leave the wall. The inner wythe often has damp-proofing on the cavity side. This layer also works as an air barrier. The...

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Masonry load-bearing walls support floors and roofs and carry those loads down to the foundation. They are built from brick, stone, or concrete masonry units. These walls rely on compressive strength, which means they can resist pushes from above very well. Masonry walls may be reinforced or unreinforced, depending on the building needs. They carry dead loads and live loads while using working stresses that stay below the materials' ultimate strength. That safety margin helps the structure...

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Masonry Curtain Walls and Support Systems

Masonry curtain walls use brick or stone veneer as an exterior cladding system. The veneer is supported by the building structure, so the wall can be both attractive and functional. Two main construction methods are used for these walls. One method builds the masonry units in place through traditional layering. The other uses prefabricated panels that are assembled on the ground and then lifted into position. In traditional construction, steel shelf angles attached to the spandrel beam carry...

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How Masonry Walls Gain Extra Strength

Post-tensioned masonry walls gain extra strength from high-strength steel rods or flexible tendons. These tensioning elements are anchored to the foundation and run vertically through the wall. In some walls, they sit inside the cores of the masonry units. In others, they are placed between the masonry wythes, or layers. The wall is built first with the tensioning elements already in place. After the mortar cures fully, the wall is tightened. Steel rods are tensioned by turning nuts against...

cavity drainage and flashings in masonry walls

cavity-drainage-and-flashings-in-masonry-walls

Moisture Control in Masonry Cavity Walls

Masonry cavity walls use a gap between two wythes, or wall layers, to help control moisture. The cavity is usually at least 2 inches wide, and it may contain insulation. Even with insulation, a clear space of at least 1 inch is kept so water can drain away. Some walls also use a continuous drainage mat to reduce the needed space while still moving moisture out. Weep holes are another key part of cavity drainage. These openings sit at the base of the cavity and let collected water escape. They...

thermal insulation in masonry walls

Masonry Wall Insulation Options

Masonry wall insulation can be placed on the outside, inside the wall, or on the interior surface. The best choice depends on the climate, the building design, and whether the wall is being built new or retrofitted. In hot, dry climates, masonry can help smooth indoor temperatures by absorbing heat during the day and releasing it at night. In many other climates, extra insulation is needed to improve thermal resistance. One common exterior method is an Exterior Insulation and Finish System, or...

expansion and contraction in masonry walls

expansion-and-contraction-in-masonry-walls

Masonry Wall Joints for Temperature and Moisture

Masonry walls change size slightly as temperature and moisture change. Builders account for this movement so the wall does not crack or shift out of place. Thermal movement is usually easy to measure and plan for. Moisture movement is harder to predict. New clay masonry units often absorb water and expand over time in normal outdoor conditions. New concrete masonry units behave differently. They usually shrink as they lose extra moisture gained during production. These opposite changes make...

movement joints in buildings

Buildings are designed to handle movement from temperature changes, moisture changes, and structural deflection. If these changes are ignored, they can cause visible damage or even unsafe conditions. Movement joints give building materials room to move without creating distress. Working joints are the simplest type. They are placed during construction and help materials cope with change as the building goes up. Shingled roofs and wood bevel siding are common examples because they can move with...

types of building separation joints

Building Joints for Movement and Stability

Building separation joints help large or complex buildings move in a controlled way. They split a structure into smaller, separate units. This reduces stress when the building shifts under different forces. The joints are grouped into three main types: volume-change joints, settlement joints, and seismic separation joints. Volume-change joints handle expansion and contraction caused by temperature changes and moisture changes. They are placed where the building mass has discontinuities,...

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Stopping White Salt Crystals on Masonry

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mortar joint deterioration in masonry

Repairing Damaged Mortar Joints in Masonry

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masonry-in-cold-and-hot-weather-conditions

Protecting Mortar During Weather Changes

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Masonry Paving Materials and Base Layers

Masonry paving uses bricks, stones, and concrete masonry units to create durable walking and driving surfaces. These materials are selected for their shape, color, strength, and resistance to abrasion and weathering. Masonry units can be used in different paving setups depending on the site and the load they must carry. Some paving systems are installed dry on a thin sand layer over a gravel base. Others are set in mortar or asphalt on a concrete slab. For areas with heavy vehicular loads, a...

key terms and concepts

Learn how movement joints help buildings handle temperature, moisture, deflection, and cracking with examples from roofs, walls, masonry, and concrete.

How Buildings Handle Structural Movement | JoVE K12

JoVE Core Civil Engineering provides a foundational exploration of essential construction materials in civil engineering, focusing on bricks, stones, steel, wood, and concrete through easy-to-understand animated videos. This collection covers the properties, manufacturing processes, and practical applications of these materials. Additionally, the accompanied science-in-action videos demonstrate the research experiments performed in laboratories.

civil engineering

How Buildings Handle Structural Movement

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