Fabrication, Supply and Installation of Bespoke Steelwork
Project Overview
Assesmont was appointed to deliver a full structural steelwork package at York House, 45 Seymour Street, located within the Hyde Park Estate near Marble Arch. The building is a reinforced concrete (RC) frame typical of the area, undergoing significant internal redevelopment across multiple floors.
Our team provided fabrication, supply and installation of bespoke steelwork designed to support new slab openings, strengthen existing RC elements and facilitate architectural reconfiguration. All works were completed in accordance with EN1090‑2 Execution Class 2/3.
Scope of Works
Multi‑floor steel fabrication & installation across the Floors 2 to 5, Assesmont delivered:
- New steel columns (PFC, RHS and UC) fixed to existing RC walls and circular RC columns
- Trimming beams to support new openings formed within the RC slabs
- Large UC beams incorporating service penetrations, stiffeners and splice plates
- Strengthening plates welded to existing steel members
- Metal deck support plates for new composite floor zones
- Custom brackets, cleats and connection plates
- Red‑oxide primer coating to all specified items
Our in‑house drawing office produced GA drawings, fabrication drawings and connection calculations, ensuring full coordination with the structural engineer.
Working Within an Existing RC Structure
York House required careful planning and precise execution due to the nature of the existing RC frame:
- 280mm RC slabs requiring temporary propping during cutting
- 600mm circular RC columns requiring resin‑anchored steel straps
- Existing PFC beams integrated into new strengthening works
- Resin‑anchored connections requiring scanning to avoid reinforcement
- Restricted access and lifting constraints typical of Seymour Street buildings
- Strict sequencing to ensure slab support before demolition
Our installation team worked continuously to maintain programme efficiency and ensure all steel elements aligned with the existing structure.
Key Project Highlights
- Delivery of over 50 bespoke steel components across four floors
- Installation of major UC beams with complex web openings and stiffener arrangements
- Strengthening of existing steel columns using new PFC sections and welded plates
- Integration of new steel columns to support future architectural features
- Full compliance with EN1090 and BC Structural Design requirements
- Works completed in continuous visits to minimise disruption
