Structural Retrofitting, Nairobi

Project overview

Roleko strengthened an existing reinforced concrete building in Nairobi by introducing new support beneath the suspended slabs at parking level, without demolition and while the building and its services remained in use. New steel beams were installed tight to the slab soffit on brackets anchored to the existing columns, with non-shrink grout providing positive load transfer.

Scope of works

Verification survey of the existing structure and services, and setting out of the new steelwork
Access restriction, protection netting and signage in an occupied building
Off-site fabrication of steel beams, end plates and bearing brackets
Anchored connections to the existing columns and grouting of the slab interface
Pre-formed web openings so that live drainage, fire-fighting pipework and cable trays remained in service
Making good of finishes around the connections

Capability demonstrated

Structural strengthening of occupied buildings: precise survey, off-site fabrication, mechanical anchorage to existing concrete and installation around live services, with controlled access for the safety of occupants.

Photographic record

**Plate 1:** New steel universal beam installed tight to the existing slab soffit, with the grout packing visible along the top flange.

**Plate 2:** Beam to column connection with bolted end plate and bearing bracket at the parking level.

**Plate 3:** Beam end plate seated on a fabricated angle bracket anchored to the existing column.

**Plate 4:** Beam web shaped around existing fire-fighting and water pipework, which remained live throughout the works.

**Plate 5:** Pre-formed web opening allowing an existing drainage pipe to pass through the new beam.

**Plate 6:** Completed beam spanning between supports, grouted to the slab soffit.

Project overview

Scope of works

Capability demonstrated

Photographic record

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