Presented by:

Wandie Olivier, Pr. Eng

Recent Road Construction Experiences in the Western Cape and South Africa

SARF AGM/Seminar 10 October 2019

Project: Contract C1046Old Oak Bridge Demolition and Reconstruction for

N1 Widening

Old Oak Bridge Demolition

Old Oak Bridge Construction

Introduction

ScopeDemolition:

- Reason behind demolition- AOT- Demolition weekend

Construction

Scope of Works

Scope

Scope

Reason behind the Old Oak Bridge

Demolition

Layout

Details

Vertical clearance

Vertical clearance

Vertical clearance

Vertical clearance

Level difference

Horizontal clearance

Horizontal clearance

Accommodation of Traffic

AOT

12 – 14 May 2017

Transport Management Center

AOT

AOT

Bridge Demolition

Demolition Sequencing

1. Remove asphalt from bridge deck prior to demolition weekend

2. Place sand protection layer over both carriageways

3. Remove concrete slab of bridge deck4. Demolish longitudinal and transverse beams5. Remove rubble to stockpile6. Demolish bridge abutments, wing walls and piers7. Remove rubble to stockpile8. Remove protection layer from both carriageways

Bridge Demolition

Bridge Demolition

Bridge Demolition

Bridge Demolition

Bridge Demolition

Bridge Demolition

Bridge Demolition

Bridge Demolition

Bridge Demolition

Bridge Demolition

Bridge Demolition

Target

58 hours

Achieved

22 hours

Construction

Details

❖ Cast in-situ, 3-spine prestressed concrete continuous deck❖ 91.5 m long❖ 20.4 – 24.85 – 24.85 – 20.4❖ Deck depth – 1.4 m ❖ Pier – 3 columns of hexagonal shape (integral with deck)❖ Perched abutments with ear wings (pot bearings)❖ All piled foundations – 610 mm DCIS (15 m long)❖ 11° skew

Lateral Support

Piling

Piling

14 piles 16 piles 10 new piles16 existing piles

Piling

Pile number

Depth according to PIT test

[m]

Depth established

through coring[m]

1 2.66 1.85

2 2.96 -

3 3.04 -

4 1.80 1.4

5 3.55 -

6 3.05 -

7 2.82 -

8 4.32 -

Piling

Piling

Size of rig caused some design issues:

❖ Pile 14 and 69 installed out of position (950 mm)❖ Pile 2 and 14: rake direction changed

Piling

Piling

Piling

Fairbrother rig = 15 m

Construction joint

Pier

Falsework

Horizontal & Vertical Clearance

3 900 3 900900

10 880

Horizontal Clearance

900

710710 3 2003 2009 100

Horizontal Clearance

Vertical Clearance

Vertical Clearance

Vertical Clearance

Deck Rebar

Deck Rebar

Construction Joint

Post-tensioning

Post-tensioning

Post-tensioning

Drip grooves

Old Oak Bridge – 1993

Thank You