Spatial Structures, Wood-Based Panels, and Concrete in Construction
Components of Spatial Structures (Steel Mesh)
Steel Profiles
Steel profiles (hot or cold-rolled) may have different sections:
- Open profiles: I, M, U, L
- Closed profiles: Circular, square, and others
Knots (Connections)
The connections are key to achieving a stable structure. Several methods exist:
- Welding: Requires extensive non-destructive testing to ensure proper execution.
- Screws: Transmit applied forces, supporting shear or reactions in the section. The usual practice is to place 2 screws per connection.
- High-strength bolts (ART): Do not support the load directly but rely on friction between compressed surfaces.
Types of Spatial Structures
- Stereo Structures
- Tensioned Structures
- Deployable Structures
Advantages of Spatial Structures
- Conceptually simple and economical for large spans
- Lightweight, stable, stiff, and high-strength
- Low maintenance requirements
- Architectural freedom
- Potential for eliminating side structural elements
- Quick and easy installation, reducing labor and facilitating the passage of utilities
Disadvantages of Spatial Structures
- Challenges in structural calculations due to their dimensions
- Need for thermal stress calculations
- Potential for damage during installation and commissioning
- Precision required in design and execution
- Special care needed for fire and corrosion resistance
- Requires significant deck space for assembly
Advantages of Plywood Over Timber
- Elimination of knots and resin nodules
- Reduced drying and cracking
- Larger available sections
Wood-Based Panels
These panels are characterized by having two dimensions significantly larger than the third and wood as the primary constituent material.
Types of Wood-Based Panels
- Particle board
- Oriented strand boards (OSB)
- Plywood
- Laminate
- Mixed or complex panels
Plywood
Plywood is made of thin layers of wood veneer (<5mm thick) obtained by rotating a log at high speed. The layers are glued together with alternating grain directions, then pressed under controlled temperature for proper setting.
Features of Plywood
- Resistance in two directions due to uniform fiber properties
- Lightweight and easily curved
- Durable and resistant, suitable for use as formwork
Laminated Board
Laminated board typically consists of a core veneer layer called the “lightened core” and a surface veneer layer. The core is composed of wood slats 2-5 cm wide and 7-30 cm long.
Joint Board (Sandwich Panel)
Joint board, also known as a sandwich panel, is composed of an inner core with adequate rigidity and insulation capacity and exterior plywood panels.
Advantages of Using Panels as Structural Systems
- Speed of installation and execution
- Energy efficiency
- Cost-effectiveness
- Flexibility
Properties of Glulam (Glued Laminated Timber)
- Stability against aggressive agents
- High strength and low specific weight
- Durability and low maintenance
- Fire resistance
Advantages of Glulam
- Allows for large wood pieces
- Better control of drying and cracking
- Efficient use of wood resources
- Construction of elements from smaller, commercially available pieces
- Design flexibility in section and size
- Ability to handle non-uniform stress effectively
- Suitable for curved pieces using three procedures: bending, notching, and lamination (lamination being the most effective)
Disadvantages of Glulam
- Requires preparation before gluing
- Higher final cost compared to solid timber
- Needs skilled labor and specialized equipment
- Design limitations due to transportation and handling constraints
Types of Concrete and Mortar
Concrete and mortar are classified based on their components and how the material is introduced.
1. Polymer-Impregnated Concrete (HIP)
Hardened concrete is impregnated with a monomer, which then polymerizes.
2. Polymeric Hydraulic Mortar (MHP)
A monomer is added to fresh concrete during curing, which then polymerizes.
3. Polymer Concrete (HP)
Aggregates are bound with a synthetic resin matrix, setting at non-extreme temperatures.
Fiber-Reinforced Concrete (GRC)
Features of GRC
- High resistance to compression, tension, bending, impact, and shear
- Low density
Composition of GRC
- Sand
- Water
- Fiberglass
- Additives
- Fillers
Properties of GRC
- Ductility
- Impact resistance
- Reduced cracking
- Durability
- Adhesion
- Fire resistance
- Impermeability
Applications of GRC
- Shotcrete
- Coatings for canals and embankments
- Concrete slabs
- Piling
- Gardening
- Sanitation
- Electricity
- Roads and highways
- Lost formwork
- Precast elements
Curtain Walling
Curtain walling is a non-structural skin that envelopes the building structure. It is classified into two main types: metal panels and panels made of other materials (timber, plastic, composite).
Heavy Cladding
Heavy cladding involves hanging stone tiles on the facade, allowing for flexible joint arrangements. Fasteners and anchors can be calculated for the sides or the interior of the tiles. When hanging non-structural components, thinner tiles can be used. Common anchor types include embedded anchors, screwed plates, and anchors formed by a substructure.
Rationalization
Rationalization involves studying technology and management methods to improve productivity and profitability.
Industrialization
Industrialization is a process that utilizes advanced technology and methods applied to the entire production process.
Industrial Processes
Industrial processes are based on scheduling and mechanization, with components manufactured in series.