Building Construction: From Foundations to Demolition
Pillars and Chains
Chains, also known as Q beams, are structural elements that resist loads. They can be made of wood, steel, concrete, HA, or a combination of these materials. Chains behave similarly to beams in bending.
Pillars
Pillars are structural elements that transmit loads to the supporting structures. They can be made of wood, steel, concrete, or HA.
Roof Structure
A roof structure is a combination of structural elements forming a lattice. These elements primarily experience axial loads.
The roof structure consists of an orderly arrangement of trusses connected by fasteners. The bottom chords of the trusses work in tension, while the top chords work in compression. The middle elements also work in compression.
Foundations
The foundation is the part of a structure in contact with the soil or rock. It supports the structure and transmits the permanent or temporary loads acting upon it.
History of Foundations
Foundation building is one of the oldest human activities, born from the need for shelter (approximately 12,000 years ago). Foundations have historically been a neglected topic in construction technology and architecture.
Mesopotamia
In Mesopotamia, with its soft alluvial ground, foundations were made using flat ceramic bricks on reed mats.
Egypt
In Egypt, religious buildings and monuments (pyramids) used rock slabs supported directly on sandstone.
The Bible
The Old Testament recommends founding structures on rock instead of sand.
Ancient Greece
Ancient Greece saw light houses of worship made of wood and stone, founded on rock mattresses.
Ancient Rome
Ancient Rome experienced significant development in construction techniques due to the empire’s expansion and the need for civil engineering (aqueducts, roads, city infrastructure) and military fortifications. Pozzolanic cement appeared, stabilizing the soil, and the first principles of architecture and construction were established. This allowed for the rational specialization of architects and craftsmen across generations.
Middle Ages
From the 5th to the 8th century, following the fall of the Roman Empire, there was a decline in construction techniques. The number of skilled architects and artisans decreased, resulting in rough structures of modest proportions.
Pre-Romanesque Period
Rubble mixed with mortar or clay was placed in shallow excavations within the building’s dimensions. Foundations depended on available space, workload, and capacity.
Romanesque Period (1000 AD – 12th Century)
Large rocks and debris were placed on the outer surfaces of the building area, and the middle was filled with smaller rock debris, sometimes mixed with clay or mortar. These were virtually all shallow foundations.
Gothic Period (12th – 16th Century)
Higher quality mortar and better-cut rock blocks were used for foundations. Site selection and some subsurface recognition were practiced, without foundation extensions for columns with arches between them.
Renaissance (16th – 18th Century)
Foundation methods were similar to previous eras, with some regression. The turning point in foundation engineering was the neoclassical period.
Neoclassical Period (18th – 20th Century)
Technological advances and new materials influenced construction practices. New construction locations and the growth of cities led to land improvements over low-capacity areas.
Demolition
Partial or temporary constructions within a new project area must be demolished once materials or equipment are recovered or dismantled (e.g., hoods).
Demolition is the fragmentation of structural or architectural elements into smaller, manageable pieces for efficiency, cleaning, and structural safety.
The manufacturer is responsible for demolition according to the project owner and the work manager. Sometimes, the contractor determines the rubble and demolition product disposal area. In such cases, disposal is free or available to the client.
Demolition Recommendations
- Concrete or masonry elements should be demolished using hand tools, machinery, or explosives (with permission in special cases).
- Demolitions on surfaces to be filled should be cut flush to ground level.
- When a building occupies the site for other structures or terrain cuts, demolition should be at or above the maximum cut level.
Demolition of Walls and Architectural Elements
- Demolish using hand tools.
- For new projects, demolish walls to the foundation level.
- Demolish renovation work to the level indicated in the project.
- Demolish architectural elements carefully to avoid damaging other structural elements.
Path
Path refers to the linear localization, marking the main parallel construction axes and boundaries on the field or surface, as identified in the project.
Smoothing
Smoothing determines the height difference of one or more points compared to a known level line. This can be true or approximate, and the accuracy depends on the work.
Besides marking land boundaries and main project axes, it’s important to plot unreferenced facilities and equipment locations (intakes, drains, registration).
Excavations
Excavation involves removing soil or earth material to reach the plinth or foundation level, the road construction level, or the bottom of an excavation for a pipe.
Excavation Types
Excavations are classified as manual, mechanical, or explosive. Depth determines the difficulty:
- a. 0 to 2 meters
- b. 2.1 to 4 meters
- c. 4.1 to 6 meters
Water Pressure in Excavations
Dry excavation occurs when the material has considerable moisture.
Excavation in saturated material occurs when the material is in its natural state before excavation and the steady-state surface is exposed to water, or when the groundwater level decreases during excavation and construction.
Excavation in water: Lowering the water table during construction is achieved by pumping. If this isn’t feasible, the excavation is considered “in water.”