Contractors World

Contractors World
The free online digital publication for
construction, demolition, mining and quarrying industries.

Contractors World 2010 Volume 1 Issue 10
Forward: Print Page Register (free) Bookmark Page

cw cw cw cw cw Buyers Guide cw cw cw

cwmags blog

Read breaking news


previous page   PAGE 13    next page

back copies


Sponsor a tree
by planting
your logo
in our
virtual forest
to aid the
Lighthouse Club
Benevolent Fund

The 410 m long Mgeni Viaduct forms part of a provincial dual carriageway which is vital to infrastructure development in the city of Durban, South Africa.

 

 

The 410 m long Mgeni Viaduct forms part of a provincial dual carriageway which is vital to infrastructure development in the city of Durban, South Africa.

 

 

SOUTH AFRICA
Technology pushed to extreme on the
Mgeni Viaduct bridge

With a contract value of US$27 million, the 410 m long Mgeni Viaduct forms part of a provincial dual carriageway which is vital to infrastructure development in the city of Durban, South Africa. It bridges the Mgeni river to link residential and industrial zones in the greater Durban area, as well as providing a link to the new King Shaka Airport.
The viaduct is an incrementally launched structure that comprises nine spans on a circular vertical curve, with its lowest point approximately two thirds along the length of the bridge.

The viaduct consists of two independent, prestressed concrete single-cell box girders with a total length of 410 m, and has nine spans of 34 m, 36 m, 6 x 50 m and 40 m. Each deck is 14.4 m wide x 3.7 m deep, and is designed to carry three 3.5 m lanes in each direction. The decks are separated by a 3 m wide raised median and bordered on each side by precast Jersey barriers.

The deck weighs 25 t per meter and follows a constant, sagged vertical curve with a radius of 3.7 km, the east abutment being 8.7 m higher than the west abutment.

The piers are hollow slipform structures founded on solid rock and secured by rock anchors. They vary in height from 15,5 – 50 m (the highest four piers were stayed during launch). The deck structure is lead by a 30 m long, 56 ton steel nose, and the deck is cast in 18 segments varying from 11 and 25 m.

    Extreme care was necessary when launching the  ridge segments as they were down a 9% gradient so measures had to be taken to counteract gravitational forcesThe bridge substructure is founded on spread footings, and the piers located in the floodplain are anchored into the bedrock using rock anchors. The piers are hollow structures with a constant wall thickness of 350 mm, which were constructed using a sliding shutter system. The tallest pier is approximately 50 m high at the deepest point of the river valley. The tallest four piers were stayed to prevent excessive deflection during the launching process.

Extreme care was necessary when launching the ridge segments as they were down a 9% gradient so measures had to be taken to counteract gravitational forces

Rumdel Cape formed a joint venture with two other contractors. These contractors are undertaking the work for the KwaZulu Natal Department of Transport’s Vukuzakhe programme in which 40% of the workforce are black youths. To increase skills, an unusual aspect of this contract is the fact that the training expenditure is budgeted at 1.5% of the contract value. Thereby ensuring a legacy of skilled construction personnel once the project is completed.

The main elements of this project are as follows: 16,000 m³ of concrete batched on site using chilled water to control concrete temperature; 1,550 t of reinforcing, 5,600 m² of formwork, 16 piers up to 50 m high and two decks, simultaneously launched at a starting gradient of 9% down slope, requiring 350 t capacity hydraulic hollow cylinders - the largest used in South Africa to date.

[cont . . ]

 

 

 

previous page   PAGE 13   next page

 
red divide
CW Contractors World - the digital publication for construction industry

Contractors World Magazines are published by VVV Limited
©VVV Ltd 2010 All Rights Reserved

Publisher: Roger Lindley
Content compiled and edited by:
Roger Lindley MCIM
Nick Johnson

Page updated: 25-Nov-2010

CP&E Contractors Plant & Equipment
Read our other publication for up-to-date information on new plant and equipment.
CLICK HERE


cmldir.com
Online Buyers Guide of Construction, Quarrying & Mining Suppliers

Contractors World - Eco Friendly publishingBy reading this page on line you are helping to save trees.
Trees saved up to November 15 2010: >160
See our
virtual forest


Support the Lighthoue Club Benevolent Fund by sponsoring virtual trees Support the Lighthouse Club Benevolent Fund by sponsoring virtual trees


CONTRACTORS WORLD MAGAZINES
CML House
7 Bell Mead
Sawbridgeworth
Herts CM21 9ES
UK
Tel: +44 1279 600598
Email: info@cwmags.com
URL: http://cwmags.com

To advertise in Contractors World see details at  http://cwmags.com/extras/media_kit/advertising.html

Contractors World, CP&E - Contractors Plant & Equipment and the CW Supplements are independent publications published through CWMags.

The mention of companies and/or products within the editorial pages or in advertisements does not infer any endorsement by the publisher or editors. All editorial is freely given, without conditions and at the sole discretion of the editor. Opinions expressed by contributors are not necessarily those of the publishers. Copying, reproduction, decoding or disassembly of content or computer code by any means of any part of the publication is prohibited unless prior approval is provided by VVV Ltd in writing and confirmation received of agreement with any terms and conditions applicable. PDF version may be downloaded for personal use but no content may be used for promotional purposes or copied to web sites.