40 Leadenhall Street

London
p1

Story

40 Leadenhall is one of the biggest schemes to have ever received planning permission in the City of London. The project was uniquely challenging because of its sheer scale.

The building’s stepped design, reminiscent of the classic North American skyscrapers of the early 20th century, cascades down towards the river Thames, and somewhat resembles Batman’s Gotham City.

We were appointed to deliver a 3-level basement with complex shoring props for partial top down and traditional blue-sky construction. The superstructure was a steel frame with composite slabs around two large cores, North and South, rising to levels 37 and 17 respectively.

The site mobilised in August/September 2020 after an extensive period of design, planning and preparation.

3 levels of basement
2 cores
h1

highlights

Substructure Works

The construction of the three storey r.c. waterproof basement at 40 Leadenhall took place across four fronts. Blue sky excavations were executed in the north and south cofferdams. The general basement in the northern half of the project was built in a top-down manner while the southern half was built traditionally using ‘blue sky’ methods. Twin level permanent and temporary r.c.gantry slabs/excavator platforms to the north, east, and south elevations, were connected using a suspended r.c. haul road supported on plunge columns. Detailed planning, professional execution and conscientious monitoring resulted in the safe and successful delivery of the excavation, propping and construction of the permanent work.

North and South Pile caps

The 37 storey northern core is founded on a 2.5m deep, 1500m3 waterproof reinforced concrete pile cap. The foundation was cast in a single, uninterrupted operation. Ahead of casting, very careful technical consideration was given to the early age thermal behaviour of this exceptionally deep element. Seasonally sensitive concrete mixes and bespoke reinforcing were specified, as well as a thermal monitoring regime to ensure the structural performance of one of the project's most critical structural elements. Careful planning ensured the successful delivery of 1500m3 of concrete using five, carefully located mobile concrete pumps. This was achieved over a period of 6.5 hours. The similarly sized south core pile cap was approach in a similar fashion.

North and South Core Construction

Like many of the City’s new landmark office buildings, the north core of 40 Leadenhall was designed to service vast space requirements, acting as both the backbone and central nervous system for the northern portion of the structure, and accommodating 16no lifts, 2no escape stairs, 5no service risers. The construction necessitated the commissioning of one of Doka’s largest and most efficient jumpform yet. Paramount to AJM's design brief was the provision of safe and secure working areas for operational personnel and visitors. The rig was also designed to facilitate advanced installations of lift cars, structural steel, facade elements and permanent steel stairs.

Low carbon construction

As part of our strategic commitment to low carbon construction methodology and the elimination of diesel operated plant, we invested in the latest low carbon technology from Schwing to place all of the concrete, successfully climbing two electric placing booms ahead of the build and supplying them using a fully electric static concrete pumps.

Project
40 Leadenhall Street
Architect
MAKE
Engineer
WSP
Contractor
Sectors
Commercial
Schemes
Services
Substructures
Superstructures
Core Construction
High rise
Location
London
Status
Current
Project summary
Project summary
Project
40 Leadenhall Street
Architect
MAKE
Engineer
WSP
Contractor
Sectors
Commercial
Schemes
Services
Substructures
Superstructures
Core Construction
High rise
Location
London
Status
Current

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