Overview
Track building settlement and structural movement with precision optical surveying, safeguarding neighboring properties throughout every phase of your construction project.
Our engineers install reflective prism targets on adjacent facades and take baseline measurements using a precision total station. Movement in north, east, or vertical axes is detected and documented at each visit, providing early warning before structural damage can occur.
Why Liberty Inspection
Liberty Inspection Corp brings PE-level expertise to every optical monitoring engagement, delivering accurate, traceable measurement data that satisfies NYC DOB requirements and protects project stakeholders from liability throughout the construction process.
Precision Surveying
High-precision total station equipment detects millimeter-level movement in three spatial axes.
Baseline Established
Initial readings are taken before work begins, providing a certified reference for all future data.
Multi-Point Coverage
We install monitoring points across all critical exposures of each adjacent structure on site.
NYC DOB Compliant
Reports align with NYC Tenant Protection Plan and Building Code structural monitoring standards.
What We Provide
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Target Installation:
Reflective prism targets are fixed to building facades at key structural points across all monitored exposures, providing comprehensive three-dimensional coverage. -
Baseline & Follow-Up Readings:
Initial readings establish certified baselines before work begins. Subsequent readings track changes in north, east, and vertical directions over time. -
Settlement Reports:
Each monitoring cycle produces a certified report comparing current readings to the established baseline, clearly flagging any movement that exceeds allowable thresholds.
Common Questions
What is optical monitoring used for in construction?
It measures whether adjacent buildings are physically moving or settling due to nearby excavation or foundation work, providing early warning of structural distress before visible damage appears.
How many monitoring points are typically installed?
The number varies by project scope. Liberty typically installs 8 to 12 monitoring points per structure, covering all exposed faces to ensure comprehensive settlement detection across the building.
How accurate is optical monitoring equipment?
Our total station equipment measures to sub-millimeter accuracy. Readings are referenced to fixed control points located away from the active construction zone to ensure measurement integrity.
When are follow-up readings taken after baseline?
Follow-up readings are scheduled based on construction intensity and phase. During active excavation or foundation work, increased frequency monitoring may be required by the DOB.
What happens if settlement exceeds the threshold?
Our PE issues an immediate notification to the contractor and owner. Construction affecting the monitored structure is suspended pending engineering review and implementation of protective measures.
