JUNE 2019 Transport for London - Projects & Programmes Directorate Construction Management Team
Value Engineering and Dealing with the Unexpected in Excavation Ciara Mcloughlin, Katherine Vick & Gary Ward
Top Tip for VE is to ‘COPE’ Cost
Opportunities
Purpose
External/ Environment Identifying Value Engineering Opportunities
Different Materials Alternative construction methods Alternative Suppliers Traffic management Construction phasing and timing Collaborative working Identifying Value Engineering Opportunities: Extruded Kerbs Identifying Value Engineering Opportunities: Materials
Design Solutions
Standard asphalt Full depth concrete Grouted Macadam reconstruction
Dealing with the Unexpected in Excavation What are Stats/Utilities? Choosing methods of stats investigation
There are a number of factors to take into consideration when planning investigation works, including the following;
• Nature of existing area – footway/carriageway, urban/rural area, volume of traffic/pedestrians, limitations to access, lane rental charges
• Design proposals – proposed construction depths & change in levels from existing to proposed, size, extents and location of areas to be excavated
• Budget & Risk – Are the cost of investigation works proportionate to the cost of the scheme and level of risk involved Ground Penetrating Radar (GPR) Surveys
What is GPR?
• A GPR survey is used to detect buried utilities and structures/features • The survey can be undertaken using a hand pushed array GPR system or a vehicle mounted system • A GPR transmitter and antenna emits electromagnetic energy into the ground. When this encounters a buried object it may be reflected or refracted back to the surface GPR vs other investigation methods
Option 1: Undertake slot trenches in approximately 5 no. Due to high volume locations – £2,000 of pedestrians in area and risks Footway cut-backs & associated with relocation of controlled closing controlled crossing points crossing points non- Option 2: Undertake intrusive works GPR survey in required favoured (GPR) locations – £1,295 Advantages of GPR over trial holes (cont.) • Non-intrusive – mobile GPR survey in carriageway & hand held in footway i.e. No TM required (mobile works) • Less obstruction in busy area (no barriers in place around excavation) • Less risk to pedestrians • No permits required • No incursion of lane rental charges Estimating the costs from a GPR Survey 18 Example utility chambers 19 How can utilities affect a scheme ? 20 21 22 Camberwell Town Centre Proposed Design
Deep BT shaft clash with kerb and levelling issues with dropped kerb transition 23 24 25 Camberwell Town Centre 26
Original Proposed Design Revised Design 27 Diversions and Co-ordination of works Section 81
Duty to maintain apparatus (1)An undertaker having apparatus in the street shall secure that the apparatus is maintained to the reasonable satisfaction of— (a)the street authority, as regards the safety and convenience of persons using the street (having regard, in particular, to the needs of people with a disability), the structure of the street and the integrity of apparatus of the authority in the street, and (b)any other relevant authority, as regards any land, structure or apparatus of theirs; Future Proofing Excavation Discoveries Archaeology Discoveries King In A Car Park 33 Quiz ! (I hope you've been listening) 34
What does GPR stand for ? 35
How long does it take for concrete to set ? 36 True or False : ‘The road network that the Romans built is still largely in place as modern roads today’ 37
What stone was used to build Buckingham Palace ? 38 Utility covers in the carriageway are no longer skid resistant.
Who is responsible to replace the cover ? 39
Who was discovered in Leicester Car park ? 40 Sir Giles Gilbert Scott is a British Architect he designed Waterloo bridge. But what else is he known for ? 41 42
What does GPR stand for ?
Ground Penetrating Radar 43
How long does it take for concrete to set ?
24 to 48 hours 44 True or False : ‘The road network that the Romans built is still largely in place as modern roads today’ TRUE 45
What stone was used to build Buckingham Palace ?
Portland stone 46 Utility covers in the carriageway are non longer skid resistance .
Who is responsible to replace the cover ? Under section 81 - the utility provider is responsible for the maintenance of their asset 47
Who was discovered in Leicester Car park ?
Richard the 3rd 48 Sir Giles Gilbert Scott is a British Architect he designed Waterloo bridge. But what else is he known for ?
Battersea Power Station and designing the iconic red telephone box 49 Questions?
...you can come and see us on the 8th floor in Palestra or email [email protected]
We aim to make sure you have no issues/risks before you go to build