Adjustable Shoring Systems

Shoring has come a long

way from the job-built

lumber systems originally

used. Many systems now

available are modular and factorybuilt

of steel or aluminum. Metal

systems eliminate much of the cutting

and measuring necessary with

older methods. They also have predictable

load capacities, minimizing

the uncertainty involved when

using job-built systems.

Today’s shoring systems are versatile

too. Built-in or attachable

height adjustment devices, interchangeable

shore heads, and other

accessories enable both wood and

metal systems to accommodate different

shoring conditions.

To help speed construction, especially

on multistory projects, many

shoring systems are designed for

fast erection, disassembly, and relocation.

Fast-attach clamps, snap

locks, integral couplings, and other

connection devices reduce the need

for nails, screws, and pins. After

shores are assembled, workers can

sometimes roll, crane-lift, or skid

them from one location to another

without disassembly, depending on

the system used.

Because adequate shoring is critical

to the safety of a construction

project, a primary consideration in

choosing a system is its load capacity—

shoring must be able to support

concrete and formwork loads

until the concrete becomes structurally

self-sufficient. Of equal importance

is adequate bracing for

any shoring system selected. Some

of the systems described here have

their own bracing; others require

added braces or struts.

With the many shoring systems

available, you probably will find several

systems that meet a project’s

load requirements. To choose from

these systems, select the one that

best meets project needs for adaptability

and speed of erection or relocation.

The following overview can help

you match a shoring system to project

re q u i re m e n t s. It describes six

types of adjustable shoring methods

and some of the features and capabilities

of systems available in each

category.

Single post shores

A post shore is a vertical support

generally made of steel, aluminum,

or wood. It can be used alone or in

combination with other shoring

systems and is often used for

reshoring.

Metal post shores typically have

two parts: a base tube with a threaded

collar and a staff tube of smaller

diameter that fits into the base (Figure

1). Tubes can be round or

square. Round-tube systems are

available with maximum load-carrying

capacities of 5,000 to 10,000

pounds. Square-tube systems have

much higher load-carrying capacities

(about 20,000 pounds). The

safety factor (ratio of ultimate load

Adjustable shoring systems

Types available and how they work

BY ANNE SMITH

Figure 1. The components of a metal

post shore. A lock pin, inserted into

the desired hole, connects the staff to

the base and determines the shore

height. A handle on the base tube’s

threaded collar allows fine height

adjustment.

to allowable load) for both squareand

round-tube systems ranges

from 2.5:1 to 3:1 as recommended

by the Scaffolding, Shoring and

Forming Institute Inc. (SSFI).

Many metal post shores use a pinand-

hole system for adjustable

heights of up to about 16 feet. The

staff has a series of holes spaced at

equal increments, usually 4 or 5

inches. A pin, inserted into the desired

hole, connects the staff to the

base and determines the shore

height. After the shore is in position,

an