Graphics CM 220 Quiz 2

What is the foundation’s job?

Supports the building and transfers loads into the ground, Limits movement that can damage the structure, and connects the structure to resist sliding or uplift

Footing

a base that spreads a wall or column load

Foundation wall

supports the structure above

Pier

a vertical support beneath a beam or column

Subgrade

The prepared ground beneath construction

Dead Load

the weight of permanent building components

Live load

the people, furniture, and movable contents

What causes lateral load and uplift?

Wind and earthquake forces

Bearing capacity

the ground’s ability to carry pressure

Settlement

the downward movement under load

Differential settlement

unequal movement

What affects construction?

Groundwater and uncontrolled fill

Where do loads pass?

through the building and foundation into the ground

A geotechnical report when excavating includes

soils, groundwater, and recommendations

Structural drawings when excavating include (think drawling keys)

dimensions, elevations, and reinforcement

Specifications when excavating include (process and details)

materials, testing, and execution requirements

Site information when excavating includes (existing and surrounding)

utilities, access, neighboring structures

Shallow foundations

loads that spread near the surface

Types of shallow foundations

spread footings, strip footings, and mats

Deep foundations

loads that transfer through deeper elements

Types of deep foundations

driven piles and drilled shafts

What does an isolated spread footing do?

supports one column

What does a continuous strip footing do?

supports a wall

Footing size

depends on loads and ground conditions

Basements

usable space below exterior grade

Crawl spaces

a shorter space beneath a raised floor

What do Below-grade walls do?

resist pressure from surrounding soil

What are Slabs on grade?

Concrete floor slabs poured directly on the prepared ground

How do Freezing Conditions affect foundations?

They lift foundations in susceptible wet soils.

Typical shallow foundation sequence

1. Layout and excavation

2. Bearing inspection and subgrade preparation

3. Forms, reinforcement, and embedded items

4. Inspection, concrete placement, and curing

5. Walls, water protection, and controlled backfill

Reading Foundation Drawlings

Plan: locations, grids, footing marks, and wall layout

Schedule: dimensions and reinforcement by mark

Section: vertical relationships and elevations

Detail: connections, joints, and water protection

What does TOF stand for?

Top of Footing

What does BOF stand for?

Bottom of Footing

How is the Volume of Concrete measured?

Length x Width x Thickness

How does a footing spread the load?

It lowers the ground contact pressure

How does a deep foundation differ from a shallow one?

Deeper load transfer

What should the team verify before a pour?

Verify bearings, forms, rebar, and embeds

Why can backfilling too early damage a wall?

Because the wall hasn’t yet reached the strength and stability needed to resist the lateral pressure of soil.