Concrete & Steel Structures
Concrete and Steel Structure Execution
Once the excavation is shored and stabilized, the phase that determines the project’s real long-term quality begins: construction of the permanent structure. At Ziggurat, we execute concrete and steel structures — from foundation to the final floor — using the same technical team that designed the excavation support system. This continuity means the project moves forward without the common handoff gaps that appear between separate excavation and structural contractors.
What We Execute
Concrete Structure
• Foundations: design and construction of raft (mat), isolated, and strip foundations, sized to match the project’s geotechnical investigation results and the loads transferred from the structure above
• Concrete frame: reinforced concrete columns, beams, and slabs (flat slab or joist-block systems), with steel or timber formwork matched to the project geometry
• Shear walls: reinforced concrete shear walls for lateral resistance against seismic and wind loads, per Part 9 of Iran’s National Building Regulations and Standard 2800
• Basement retaining walls: cast-in-place basement walls with proper construction-joint sealing and waterproofing detailing, particularly on sites with a high groundwater table or adjacent to a waterway (as in our Elahiye project) Steel Structure
• Workshop fabrication of steel members — cutting, welding, drilling, and anti-corrosion coating
• On-site erection with welded or bolted connections, depending on the lateral load-resisting system (moment frame or braced frame)
• Truss and light steel construction for long-span bays (including IPE profile truss members)
• Dimensional, plumbness, and level checks before and after erection
Why Integrated Excavation-to-Structure Execution Matters
Splitting the excavation contractor from the structural contractor is one of the most common sources of delay and dispute on building projects. When the excavation support design (nailing, anchoring, or cross-lot bracing) and the permanent structure execution sit within one organization:
• The transition from excavation completion to foundation concreting happens without unnecessary standby time
• Excavation and structure are scheduled as a single program, not two separate schedules that need to be reconciled later
• Interface issues between the temporary support system (nail bars, anchor tendons) and the permanent concrete wall are resolved by the team that has understood both sides of the problem from day one
• Dewatering and waterproofing continuity is maintained from excavation through structural completion, with no gap in accountability between contractors
• Project overhead — equipment, site safety management, supervision — is shared across both phases, creating real cost savings Execution Process
1. Design review against the geotechnical report: before execution starts, structural drawings are checked against the geotechnical investigation and the excavation support design to catch mismatches in footing levels or bearing locations early
2. Foundation construction: rebar placement, formwork, and concrete pour, with on-site slump testing and cube sampling at every pour
3. Frame construction: floor-by-floor progress for concrete structures, or bay-by-bay for steel, with verticality and level checks at every stage
4. Inspection and quality control: visual and, where needed, ultrasonic weld inspection for steel frames, compressive strength testing at 7 and 28 days for concrete, and as-built drawing preparation
5. Staged handover: each completed section is handed to the client with technical documentation, lab test reports, and quality control records
Standards and Quality Control
Structural execution follows Iran’s National Building Regulations:
• Part 9: design and execution of reinforced concrete buildings
• Part 10: design and execution of steel structures
• Standard 2800: Iran’s seismic design code for buildings
• Iranian Concrete Code (ABA): design and execution requirements for concrete structures
Cube sampling from every concrete pour, compressive strength testing at 7 and 28 days, and visual plus instrument-based weld inspection for steel frames are part of the standard quality control routine on every project we run.
Material Quality Control
Selecting a concrete mix design suited to the project’s environmental exposure (such as sulfate resistance where Tehran soils require it), checking rebar mill certificates, and obtaining mill certificates for the structural steel plates and profiles used in the frame are part of our material procurement process. This control starts at the material ordering stage, not just during execution, so any discrepancy is caught before materials reach the site.
Why Ziggurat?
• One technical team spans geotechnical investigation, excavation support design, and final structural execution
• A track record on deep excavation projects across Tehran (Iran Mall, Elahiye, Yousef Abad, Shahrak-e Gharb) where the excavation-to-structure transition was managed in-house
• A single schedule for excavation and structure, with no standby time between two separate contractors
• Documented quality control at every stage, from foundation rebar to final steel erection
Frequently Asked Questions
Do you execute concrete and steel structures as a contract separate from excavation?
Yes. If the excavation support system was designed and executed by another team, we review the existing reports and drawings and take on foundation and frame execution independently.
How is integrated excavation-to-structure execution different from the usual two-contractor approach?
In the usual approach, there is typically a standby period between excavation completion and the start of foundation concreting while the structural contractor takes over the site, assesses conditions, and mobilizes. Integrated execution removes or sharply reduces that gap because both phases run under one technical team.
Is steel or truss construction recommended for long-span projects? The choice between concrete and steel depends on the applied loads, span length, required construction speed, and project budget — this is assessed with the client during design, before execution begins.
What precautions are taken for structure execution on sites with high groundwater? On these sites, basement wall waterproofing, temporary dewatering during execution, and coordination with any dewatering system in place are built into the foundation design from the start, so that leakage or hydrostatic pressure doesn’t become a problem after the structure is complete.