Structural Engineering Design

Link work for a range of developer and contractor clients in different sectors to provide structural engineering design services for new buildings. The design process can start as early as the site acquisition phase with input into ground conditions, level options, road access and drainage options informing development appraisals and leading to production of information for Planning Application. A range of different foundation and superstructure options may be considered in a feasibility design phase alongside other designers and professionals. Design solutions are developed towards construction information with Link input varying to suit procurement processes. Link are normally also involved in the construction phase site interfaces.

Link engineers have been involved in both the design of new concrete structures and modification and appraisal and repair of existing concrete structures. These have included multi-storey commercial and residential framed buildings using reinforced concrete columns and beams or flat slabs (traditional or post tensioned) as well as issues associated with modification maintenance or extension of ageing multi-storey commercial buildings including:

• Multi-storey residential / apartment buildings
• Offices
• Retail buildings and shopping centres
• Education centres (schools, colleges, universities etc)
• Health buildings (hospital, medical centres, care homes, hospices, specialist treatment centres)
• Specialist forms of construction encountered include:
  • Precast concrete elements both floors and frames
  • Post tensioned flat slabs
  • Cast insitu rib slabs
  • Beam and block floors
  • Composite floors with either precast or steel elements combining with insitu concrete to form a floor construction
• Link have also developed a particular specialist expertise in appraisal and repair of ageing multi-storey car parks

Link engineers have been involved in both the design of new steel structures and modification, appraisal and repair of existing steel structures. These include:

• Multi-storey retail, commercial, health and residential buildings with steel columns and steel beams supporting timber or concrete floors. Some of the concrete floors rely on composite construction with profiled metal or precast concrete decks acting compositionally with steel beams to create a composite floor construction.
• Steel frames also include large span portal frame and truss frame structures for distribution, manufacturing and retail buildings. Steel structures in manufacturing buildings can incorporate heavy or light craneage as well as other secondary structures to support manufacturing processes in the form of gantries, multi storey mezzanines, conveyors or other systems.
• Some older steel structures can incorporate historic materials (eg. rivets, cast iron, old steel types) and section sizes. Steel roof trusses and trussed columns are also common in older buildings.

Link engineers have been involved in both the design of new foundations and the modification, appraisal and repair of existing foundations, these have included:

• Pad foundations
• Raft foundations
• Ground beam and strip foundations
• Trench fill and strip foundations
• Piled foundations using a variety of different types of piling such as:
  • Driven precast
  • Driven steel
  • Driven cast in situ
  • Continuous flight auger
  • Augured
  • Specialist sleeved or voided piles to limit load transfer into upper ground near tunnels sewers or other sensitive structures or to provide acoustic isolation to buildings from ground borne sound.
• Ground improvements for foundations including chemically or mechanically stabilised ground and vibro compacted ground under pad or strip foundations

A building structure can be considered to be an assembly of structural elements which act together to serve to transfer all appropriate combinations of actions (dead weight, wind, snow, imposed loads etc) safely and robustly into foundations and hence the supporting ground without any of those elements being overloaded or deflecting excessively. The Building Regulations (Part A – Structure) require a building to be constructed to transfer loads safely as described above. The Approved Document to Part A of the Building Regulations includes a list of British Standards and other documents which are references for good design practices for different building types and materials. Although use of these documents is not mandatory under the Building Regulations they are considered to encompass good design practice and are used as the basis of design for most projects. The process for designing building structures often includes preparation of calculations for designed structural elements to check their adequacy in the intended structural solution. (Some simple structural elements can however be designed using approved design tables or other non-calculation methods.). Structural calculations normally include evaluations of loads which are to be applied to individual structural elements and then analysis of those elements with loads applied to consider serviceability and strength performance. In this context the calculations undertaken will often reflect the requirements to satisfy British Standard methods of evaluation. Although there is no Building Regulations requirement provide calculations to justify to Building Inspectors the adequacy of structural design it is normal for calculations to be presented. Link Engineers consider that it is good practice to produce sufficient structural calculations to demonstrate the structural adequacy of the designed structure in a form which is suitable for presentation to Building Inspectors or, where applicable, other third party reviewers. Preparation of calculations often involves the use of specially produced proprietary structural analytical computer software at the discretion of the designers (not a standardised Building Regulation requirement).

There are often occasions where Link Engineers are required to review and comment structural designs undertaken by other designers. These can include:

• Landlord review of “Licence to Alter” works – can include wholesale building modifications or minor works.
• Fund or Tenant review of development proposals
• Independent design check reviews for safety sensitive structures.
• Review of specialist supplier or contractor alternative design proposals

The structural engineering design of building elements necessarily include fundamental assumptions about the minimum standards of workmanship and material properties for the components included in the construction of those elements. Link Engineers prepare either workmanship and materials specifications for elements designed by them or performance specifications for structural elements which are defined as being defined by specialist suppliers. The Link specifications make widespread reference to British Standards for each of the types of construction and identify appropriate constraints on material properties and construction tolerances. The Link specifications also identify requirements for contractors to operate adequate quality control process to encompass both raw materials and the quality of constructed works.