The Construction of Hoover Dam Technical problems and Solutions

Hoover Dam

Lake Mead

The Dam Located on the border between Arizona and Nevada Blocks the Colorado River Hoover Dam created Lake Mead behind it Construction began 1931, initially on the four tunnels used to divert the river away from the building site

The Dam Construction of the actual dam began 1933 Nothing of this magnitude had ever been attempted before As a result there were many problems with untested solutions

Site Preparation River water diverted This was done using four tunnels, two either side of the canyon In total the tunnels spanned a length of 16,000 feet (3 miles) The tunnels were dug out using dynamite

Site Preparation Scaling the cliff walls and removing any loose rocks This work was needed to ensure that when the dam was built it would stay firmly in place and not crumble away at the edges

‘High Scalers’ The men who were given the job became known as ‘High Scalers’ The workmen were required to hang from ropes off the edge of the cliff and use jackhammers and dynamite to blast off loose rock They weighed 44lbs

High Risk Many men died from falling tools or slipping and falling off the cliff As a result the men invented hardhats to stop them getting fractured sculls from falling objects They did this by filling cloth hats with tar

Rescue A spectaculuar example of the dangers involved is a story of a man who slipped and fell. 25 feet below another worker leapt off the cliff, holding onto his rope, and caught the man’s foot. Another worker pinned the man to the cliff until he could be rescued.

‘High Scalers’

Construction Construction began in 1933 The first problem engineers faced was the sheer amount of concrete needed to build the dam A site to make concrete was first built upstream and later one was built on the edge of the canyon

Problems Another problem faced was the fact that concrete produces heat as it sets. Had the dam been created in one pour, the heat generated would have meant the dam would not have set for 125 years. This would have created cracking and erosion.

Another solution A solution was devised by engineers The dam was to be built with a series of concrete pillars, trapezoidal in shape, joined with interlocking grooves When set, the blocks were pressure grouted together

Blocks of concrete

Problems and Solutions Pouring the concrete in separate blocks was only part of the solution to the concrete problem The dam was in the middle of the desert and the heat was setting the concrete too fast

Pipes To solve this problem, a system of pipes was woven throughout the concrete and filled with cold water. This slowed down the setting process Later the pipes were removed and the holes filled with grout