Innovative capture and modeling of existing building conditions using 3D laser scanning. Entry B Submission

Transcription

1 Innovative capture and modeling of existing building conditions using 3D laser scanning Entry B Submission

2 Executive Summary As a large owner organization, understanding and developing new technologies to document as-built conditions of our capital asset inventory is a major strategic goal of our BIM Program. During 2007, our program initiated, documented and implemented numerous 3D laser scanning projects with tangible, quantified benefits. This entry focuses on our progress and influence on industry in using 3D laser scanning technology. On a project level, gains included faster, more accurate, and less expensive production of 2D and 3D models of existing building conditions. On a program level, we developed and tested a process for documenting existing conditions across a wide portfolio of building types, and provided lessons learned and sample contract language to facilitate procurement across our organization. Industry-wide our efforts has continued to foster competition and encourage market penetration of 3D laser scanning technologies. Finally, by providing detailed case studies and collaborating with industry leaders and research organizations, such as universities and SPAR Point Research LLC, we have educated ourselves and members of the community as to the potential of laser scanning technology, regarding its current state and future developments.

3 The business need for 3D Laser Scanning As an owner organization, our ability to capture, validate, and report the spatial information of our building assets (e.g., dimensions, areas, and locations of rooms; elevation/fenestration details; mechanical equipments and ductwork; etc.) has a significant impact on our core business. Specific business needs include: Real Estate Portfolio Management s reliance on available and most up-to-date spatial information to align business, management, and optimization strategies Property Development s need to provide site data and existing spatial information about the buildings to their architects/engineers for design in renovations and alterations projects Property Management s objective to ensure that the spatial alterations from any construction work is being captured in the as-builts Historic preservation officers and specialists desire to incorporate, maintain, and analyze an archive of building assets with historic significance

4 The business need for 3D Laser Scanning (2) Our organization s traditional standard practice for capturing current conditions is founded on a manual CAD process in which the most up-todate as-built information is maintained by documenting all spatial changes in two-dimensional (2D) AutoCAD-based drawings. This manual data capturing process is supplemented by spot verifications in the field with conventional survey technology such as tape measurer or point-topoint laser survey beam. Current practice is error-prone and the accuracy of the spatial information is largely dependent on the individuals producing and updating the archive drawings. Furthermore, these drawings do not account for construction tolerance and the deformations of the building over time. Reliance on spot verifications has been random and insufficient to assure the quality of the as-builts and re-measurement is frequently requested. Objectives for innovative 3D laser scanning technology adoption include improved: Historical documentation Facility condition visualization Physical deviation assessment BIM development

5 Innovative Technology 3D imaging systems are instruments that rapidly measure (typically on the order of thousands of measurements per second or faster) the range and bearing, and/or the 3D coordinates, of points on an object or within a region of interest. In general, 3D imaging uses either a pulsed time-of-flight or phased-based system to obtain 3D information of a scene, and rely on line of sight (LOS) instruments.

6 Pilot Project Implementation In 2007, 3 Pilot Projects using 3D Laser Scanning were completed: Historical Building, Brooklyn, New York Office Building, Atlanta, Georgia Campus, Miami, Florida

7 Historic Building, Brooklyn, NY Project Description On the National Register of Historic Places and designated as a New York City Landmark, this building is approximately 72,450 SF. The structure has an original 1892 section and a newer 1933 addition. 3D laser scanning was used to provide a current-condition record of the existing masonry architecture and assist in future renovation designs and terra cotta fabrication. The objective of the scanning was to provide 2D-CAD elevations required to document as-built conditions including: planning for replacement of deteriorated terra cotta cladding on the 1933 facades using new terra cotta or alternate materials; restoration of all existing granite cladding on both buildings; and replacement of the entire slate mansard roofing system on both structures. The produced elevations assisted architecture and engineering firms in developing their restoration and renovation designs.

8 Office Building, Atlanta, Georgia Project Description This 30,000 SF mid-century high-rise office building in Atlanta, Georgia was planned for rolling renovation. The building did not have 2D CAD drawings and significant deficiencies in the original construction lacked as-built documentation. Existing conditions included: aluminum window frames and glazing out of specification and requiring replacement; concrete columns, beams, and balconies constructed out of specification, with observable spalling. The primary objective of 3D Laser Scanning was to provide accurate 2D elevations of the exterior of the facility to the architects and engineers to assist in the development of force protection measures and new window assemblies.

9 Federal Campus, Miami, Florida Project Description The campus includes five federal buildings linked together with bridges and tunnels all in various lifecycle states. The site was in need of renovation. Accurate as-built drawings did not exist. The objective of this project was to use 3D laser scanning technology to provide a detailed 3D model and 2D elevations of the buildings exterior along the central pedestrian promenade, as well as develop an integrated model that incorporated the five campus buildings into a single cohesive BIM site model. The goals of the project were to assist the A/E firm construct a highly accurate as-built condition for facility and later use the model to assist in training and tracking of various circulation routes throughout the campus.

10 The 3D-laser scanning process: From Building Features to 3D model In 3D laser scanning, the x-y-z coordinates of the spatial data is collected in the time it takes a laser beam to hit a surface point and return. Similarly, a photo and color intensity of the spatial data is captured. By gathering millions of these point-specific data, a point-cloud data set can be created instantaneously in the field. Such data set can be archived for historic preservation and as-built documentation purposes, allowing users to directly query 3-dimensional spatial data (e.g., distance, ceiling height, volume, etc.) directly from the data set. Furthermore, postprocessing the data set can output architectural drawings (CAD) and building models (BIM) for specific business needs. 2D Model Building Features Point Cloud 3D Model

11 Results: 2D drawings were created from point cloud models to accurately represent as-built elevations.

12 Results: 3D models were developed from point cloud data to document building conditions.

13 Results: Accurate field measurements were captured and documented in 3D models.

14 Results: Detailed site models were created

15 Results: Historical façade work was captured in both the point-cloud data and 3D models.

16 Results: Precise conditions of distinctive windows were captured.

17 Successes on Pilot Implementations In one pilot project, independently contracted laser scanning services created an as-built 3D model that resulted in the Design Team providing monetary credit to our organization for the use of the model. Laser scanning services were able to identify several discrepancies between documented (2D drawing) and actual (existing) wall conditions. Open and competitive bidding resulted in lower than expected project costs for laser scanning services, and on several pilot projects, our organization was able to exercise all options.

18 Discernable Benefits Value: BIM technology is often perceived to benefit new construction projects only. However with 3D laser scanning, all project modernizations can benefit from the technology via as built 3D model generated with accuracy, efficiency, flexibility and non invasive methods to develop a basis for the design start and construction. Accuracy: 3D laser scanning offered rich data sets at ¼ of accuracy for a range of 3 feet to 150 feet. Even higher resolution and range would have been possible with more specialized equipment. Conventional practice relies on incorporating changes and alterations into 2D archive drawings. Laser scanning minimized the risks of incorporating design changes into prior faulty documentation, reducing the likelihood of error propagation. Efficiency: 3D laser scanning averaged 100,000 points per minute. As typical, 3D laser scanning equipment supported a 360-degree spherical coverage. In one application an entire building was scanned (with coverage redundancy) in one day using multiple teams and multiple scanners (contrast to the time it takes to perform spot measurements with tape measurer or static laser beam). Such efficiency is valuable as it minimizes the disruptions to the ongoing operations or security of our tenants. Non-Invasiveness: 3D laser scanning offers a non-invasive means and methods to document building elements that are of high historical value and may be difficult to access (e.g., ceiling space, building elevation, subterranean utility, etc.). Scanning was conducted when buildings were in operation with minimal disruption to the tenants. Flexibility: 3D laser scanning has the capability to stitch multiple scenes together with overlapping registrations. On one project, a complex site map was created from 33 scan positions by a team consisting of two qualified surveyors operating daily for two weeks.

19 Collaboration and Partnering To support these efforts and promote industry advancement, our organization has fostered: Industry collaborations with NIST, ASTM, and SPAR Point Research LLC to promote open standards and best practices. Academic partnerships with Harvard University, Carnegie Mellon University, and Stanford University to advance 3D-laser scanning technology, interoperability, and implementation processes. 5 completed and ongoing industry contracts awarded for laser scanning data capture and modeling.

20 Draft BIM Guide on 3D Laser Scanning 1: introduction Our publicly available draft BIM Guide on laser scanning captures best practices, lessons learned, and process maps and is open for industry comments and feedback.

21 Conclusions Our organization tested technologies across applications on a variety of project types including: Archiving Historic Building Elements (e.g., ornamentation details constructed in a virtual 3D computer model) Current Condition of an Existing Building planned to undergo Major Modernization (e.g., the elevation, underground utility, HVAC ductwork, and interior partitions of a 40-year old office building) As-Built Assessment of Site Conditions (e.g., the as-built site plan of an existing campus to align design with existing conditions) We created detailed Case Studies from pilot project implementation to document the lessons learned. We fostered industry dialogue and promoted collaboration in support of technological advancement and process harmonization. We developed a publicly available draft guide outlining 3D imaging services, available software applications, and implementation methods.