Photogrammetry with Drones, Rope Access, and TPAS®

Photogrammetry is the practice of extrapolating spatial relationships from photographic imagery. While the concept of photogrammetry is centuries old, today’s powerful software quickly generates a 3-dimensional point cloud of any scene or object captured with a half dozen or up to several hundred overlapping digital photographs. Two recent projects illustrate very different applications for this technology in expanding what Vertical Access can do for clients in hard to reach areas.

Using Unmanned Aerial Vehicles for Conditions Documentation and Image Capture

Work on existing structures begins with accurate as-built documentation. But what if there is no background drawing on file for use in the field?

Enter photogrammetry. On a recent project, the main façade of a building could not be surveyed with an aerial lift due to site features, leading the project team to investigate the use of an unmanned aerial vehicle (drone) to capture close-range imagery of the façade conditions as well as photographs for use in the creation of scaled, detailed background drawings.

Vertical Access’ licensed drone pilots operated a DJI Phantom 2 drone to obtain medium-range imagery for the creation of a photogrammetric 3D point cloud, as well as close-range 4K video for the conditions documentation of the structure. The field work was accomplished by a team of two pilots in less than two days and required only partial closure of the pedestrian walkway to safely conduct the drone flights.

2D elevations generated from the 3D model annotated with fault conditions in AutoCAD. Fault conditions such as cracks, spalls, and displaced masonry units were annotated digitally using the Tablet PC Annotation System (TPAS®).

Back in the office, VA used Pix4D Mapper Pro photogrammetry software to generate the point cloud, textured mesh, and 2D orthoimages of the main façade, side wings, and tower returns. The orthoimages were scaled and placed as background images in an AutoCAD drawing, and fault conditions such as cracks, spalls, and displaced masonry units were annotated digitally using the Tablet PC Annotation System (TPAS®). Condition quantities were extracted from the AutoCAD drawing into an Excel spreadsheet to facilitate repair cost estimates.

A close-range visual inspection as well as image capture for photogrammetry were completed in much less time than it would have taken to inspect the façades and obtain hand measurements using an aerial lift. The field work was accomplished with minimal disruption to pedestrians.

Deliverables from this study include a scaled 3D point cloud and textured mesh, 3D PDF model, background drawings based on orthoimages generated from the photogrammetric point cloud, and 4K video documenting façade conditions at close range, with over 800 video stills hyperlinked to conditions annotations in the AutoCAD elevation drawings.

Modeling Decorative Features of Historic Structures With Photogrammetry

A 3D3D photogrammetric models of an individual terra cotta unit, to be transformed into shop drawings for replacement units.

Restoration of historic decorative terra cotta, cast stone, or natural stone often requires extensive replacement of individual units. Erecting scaffolding for hands-on access to measure and remove existing units adds significant cost to project budgets.

Vertical Access recently used photogrammetry to aid in a pilot project as an alternative option for acquiring dimensions of existing units.

Vertical Access photographed a terra cotta spandrel panel and parapet, using existing scaffolding to gain hands-on and close-range access. The photographs were used to create 3D photogrammetric models of individual units, to be transformed into shop drawings for replacement units.

With VA’s demonstrated rope access capability, units can be photographed and modeled without the need for scaffolding, yielding a cost savings for the building owner.

Staff Certification Updates and My First Time as Trainer

Vertical Access recently conducted an in-house industrial rope access training course in preparation for third-party certification or recertification by the Society of Professional Rope Access Technicians (SPRAT). As a Level III Rope Access Supervisor with over 17 years experience in the construction industry and a Vertical Access employee since 2011, I took on the role of trainer for the first time.

We are excited to congratulate the following staff on SPRAT advancements and recertifications:

Patrick Capruso: Level II (Certified)
Kristen Olson: Level II (Recertified)
Evan Kopelson: Level II (Recertified)
Kelly Streeter: Level III (Recertified)

I also recertified to a Level III prior to taking on the role as trainer.

Other VA staff SPRAT advancements and recertifications include:

Michael Patino:  Certified to Level I
Berta de Miguel:  Recertified at Level I
Mike Russell:  Certified to Level II

What Does Rope Access Certification Entail?

Certified rope access technicians and supervisors must undergo training and recertification every three years. As part of the training, technicians review basic rope access techniques that we most often use during site work as well as more advanced skills
that are less often used, such as passing knots, rope-to-rope transfers, redirects, rebelays and horizontal aid traverse. The training also covers rope rescue techniques and mechanical advantage systems used for hauling or lowering a rescue subject or other load.

Following the training course, Vertical Access brought in an independent SPRAT Evaluator to conduct the evaluation. The evaluation and certification process includes written and oral examinations to test knowledge of safe practices for industrial rope
access and an understanding of the equipment and principles involved in rope access work. The main part of the evaluation is the skills test, in which each candidate must demonstrate a broad range of rope access skills.

What is SPRAT?

SPRAT is a membership organization that promotes the development of safe practices and standards for rope access work in the United States, Canada, Mexico and beyond. Vertical Access is a member of SPRAT and has been active in its leadership committees throughout the years.

  • Level I Technicians are rope access workers with the appropriate training, skills and qualifications to perform work under the direct supervision of a Level II Lead Technician or Level III Supervisor.
  • Level II Lead Technicians are responsible for physically conducting rope access operations and/or safety evaluations of rope access operations, including maintenance of associated access equipment, and are capable of performing all Rope Access Lead Technician duties as assigned in the employer’s rope access work program. To become a SPRAT Level II certified
    technician, Mike and Patrick were required to complete the evaluation as described above, in addition to logging 500 performing rope access work as a SPRAT Level I certified professional.
  • Level III Rope Access Supervisors are responsible for overall rope access operations on site and job site safety. Level III candidates should have current First-aid, CPR, and AED certification prior to evaluation and will have logged at least 1000 hours performing rope access work with at least 500 hours and six months as a SPRAT Level II certified professional.

 

Mike Russell Earns SPRAT Level II Certification

Mike Russell, EIT, has earned his Level II Certification from the Society of Professional Rope Access Technicians (SPRAT).  A Level II certified individual is responsible for physically conducting rope access operations and/or safety evaluations of rope access operations, including maintenance of associated access equipment and performs all Rope Access Lead Technician duties as assigned in the employer’s rope access work program.  To become a SPRAT-certified technician, Mike was required to attend a certification session and pass a written test, verbal test, and a hands-on physical performance based test assessed by a SPRAT-certified Evaluator, in addition to logging 500 hours on the job as a SPRAT Level I certified professional.

Mike joined Vertical Access in 2016 bringing with him over six years of experience working in the construction industry, both commercial and residential, specifically relating to project management, sustainable building practices, and restoration in residential and maritime environments.

He began restoring boats for the City of Charleston (South Carolina) Maritime Foundation while pursuing a degree in Historic Preservation and Community Planning at the College of Charleston.  Following his switch to the field of engineering, Mike joined a residential construction firm located on the Connecticut shoreline that specialized in the restoration and rehabilitation of barns and historic homes.  From there he went on to join Whiting-Turner, a national contracting firm where he worked as a project engineer on large scale commercial projects before joining Vertical Access in the summer of 2016.

Congressman John Faso Joins Effort to Reform New York State Scaffold Law

Congressman John Faso announced on Tuesday the introduction of innovative, new legislation entitled the “Infrastructure Expansion Act,” which would relieve some of the negative effects of New York State’s Scaffold Law by imposing a liability standard of comparative negligence on all construction projects that receive federal financial assistance. This legislation is directly intended to reduce the cost of new construction – both public and private – which is subsidized using federal funds.  The proposal would ensure that any project using federal dollars is not subject to New York law mandating “absolute liability” on the building owners and contractors.

Listen to the WCNY interview below, and read the full press release here.

September 19, 2017: Rep. John Faso and Mike Elmendorf

 

For more about the Scaffold Law Reform, visit www.scaffoldlaw.org

 

Ford Amphitheater at Coney Island: Restoration of the Child’s Restaurant

In her Applicator cover story, “The Ford Amphitheater at Coney Island and the Seaside Park,” Architect Diane Kaese highlights the redevelopment and restoration effort at the former Child’s Restaurant. For Vertical Access Preservation Technician Patrick Capruso it was a thrill to see photographs of the finished façades. As a former finisher at Boston Valley Terra Cotta, Patrick helped to sculpt a number of the 752 terra cotta units replicated for the building.

As Kaese explains, ornamental elements of the maritime motif originally modeled by Sculptor Max Keck and produced by the Atlantic Terra Cotta Company were meticulously reproduced using undercutting techniques to accentuate shadows and hide the ¼” joints required for seamless assembly.

According to Patrick, shaping these elaborate snails, ships, and seashells was both difficult and immensely rewarding.

Congratulations to Diane Kaese, Boston Valley Terra Cotta, and the rest of the project team on a job well done!

Berta de Miguel Earns Her Ph.D

Berta de Miguel has earned her Ph.D in Preservation of Architectural Heritage from Universidad Politécnica de Valencia, Valencia, Spain. She joined VA as in intern in 2011, initially focusing on our continued research into the works of the Guastavino Company in New York City.

A SPRAT Level I technician, she currently participates in Vertical Access field projects and preservation conferences.

 

Berta is our Metropolitan New York branch office manager and is a NYC Department of Buildings CD-5 Filing Representative. She co-instructed a graduate level course, “Restoration of Historic Buildings: Discovery, Design, Execution”, at Manhattan College in New York City in Spring of 2013.

Berta also participated in the award-winning biographical documentary, El Architecto de Nueva York, a celebration of the lives and careers of the Rafael Guastavinos, father and son, developers of the Guastavino vault architectural construction technique.

For six years prior to joining the VA team, Berta was a project manager of building restoration projects at Edycon, one of the top ten architectural conservation and historic preservation firms in Spain. She was responsible for managing multiple projects with large teams simultaneously, in addition to the preparation of reports to clients and institutions. Berta’s professional background also includes two years studying architectural preservation in Cuba and Belgium. She has been the restoration site project manager on more than twenty landmarks, including the UNESCO World Heritage Site Catedral de Teruel (12th century), the National Landmark Castle of Sagunto (Roman origin), and the San Martin Church of Valencia (14th century).

Congratulations Berta!

Tourist In Your Own Town: Prison Ship Martyrs’ Monument

View the latest video in the series, Tourist in Your Own Town, made by the New York Landmark Conservancy, all about the Prison Ship Martyrs’ Monument.  During the Revolutionary War, the British held thousands of prisoners on ships anchored in the East River. These prisoners represented all thirteen colonies and at least thirteen different nationalities. The Monument marks the site of a crypt for more than 11,500 men and women who died of overcrowding, starvation and disease aboard these prison ships.

Vertical Access performed a comprehensive conditions survey of the exterior granite, bronze brazier and interior brick masonry to help inform the preparation of construction documents for repairs and restoration.  More on our work at the Monument.

 

Tourist in Your Own Town: New York Botanical Garden

View the latest video in the series, Tourist in Your Own Town, made by the New York Landmark Conservancy, all about the New York Botanical Garden.

We’ve had the pleasure of working at the Botanical Garden in  the past and are currently assisting with  maintenance and access fall protection design.  (We love our “hero shots'”!)



 

Blair Kamin: Thompson Center Sale Shouldn’t Automatically Mean Demolition (Chicago Tribune)

 

In the course of its storied architectural history, Chicago has come to rue the demolition of buildings like Dankmar Adler and Louis Sullivan’s Chicago Stock Exchange. They were torn down for the usual reasons. Owners claimed they were outdated. Politicians refused to stand in the way of “progress.” Activists protested, but not enough ordinary citizens raised their voices. The Stock Exchange, whose entrance arch outside the Art Institute of Chicago forms the city’s wailing wall of historic preservation, fell in 1971-72.

Now, a new crisis looms, this one over the fate of the James R. Thompson Center, the spaceship-shaped glitter palace that is, despite formal and functional flaws, one of Chicago’s most significant works of postmodern architecture.

Read the rest of the story here.   Learn about our involvement with the Thompson Center here.

Flume Fever Afflicted: 126-Year-Old Mining Flume in Western Colorado Clings to its Secret

There is something about the tattered remnants of a 126-year-old mining marvel that keeps drawing the curious back to this remote area along Colorado 141 located in Colorado Canyon Country, mostly on public lands operated by the Bureau of Land Management, Uncompahgre Field office.

Those who keep returning to measure, survey, photograph and examine the mysterious structure known as the Hanging Flume call it “flume fever.” The afflicted wake in the middle of the night to puzzle over how enterprising but misguided gold seekers pinned a 10-mile-long wooden water chute to a sheer cliff to create a hydraulic gold separator.

Our Hanging Flume investigative team this year: Kent Diebolt, Donn Hewes, Keith Luscinski, and Kevin Dalton

Previous preservation efforts on the Flume identified the need for additional investigative work to better understand the diverse construction, innovative engineering, and significance of the Flume to mining history in Colorado.

The red sandstone cliffs of the Dolores and the San Miguel Rivers are the site of one of the longest and most intriguing heritage sites in Colorado: running parallel to the Unaweep-Tabeguache Scenic Byway, this storied and iconic western slope structure has awed international travelers and regional passersby for decades. Sparking such questions as, “What was it for?” “How long did it take to build?” “Who built it?” “And how?” Years of research by local residents, BLM archeologists, and national specialists have provided many conclusive answers however answers to the question of the flume’s construction have remained speculative at best, until now. From April 26 –May 5th Anthony & Associates, Vertical Access and Alpine Archaeological Consultants will be completing Phase Three of an Archaeological Survey funded by History Colorado and the State of Colorado Div. of Reclamation, Mining & Safety The team of experts will conduct investigation of construction methodology at approximate six drop locations.

Project Manager Ron Anthony, of Anthony & Associates, a wood scientist from Fort Collins, CO, believes the technical questions about the flume’s construction methods will be best answered with careful research and investigation.

“Construction of the Hanging Flume in the 1880s was accomplished in a time and place that we can barely imagine,” Anthony says, “It would be selfish and irresponsible to allow these construction, engineering and human achievements to vanish without doing our best to make them available for future generations.”

The flume carried 80-million gallons of water in a 24-hour period to the hydraulic mining operations of the Montrose Placer Mining Company. Taking 3 years and 25 local men to complete, the water was used to provide hydraulic power to separate gold from alluvial rock deposits which originated in the San Juan Mountains before being deposited along the Dolores and San Miguel Rivers. “We know what they built; we just don’t know how they built it and to our knowledge, the construction technology was not documented. Over 100 years have past since its construction and the flume is showing its age.”

In 2006 the Hanging Flume made the World Monument Watch list of 100 Most Endangered Sites. Since that time, the BLM has developed partnerships with the National Trust for Historic Preservation, Colorado Preservation, Inc., the Unaweep-Tabeguache Scenic Byway Association, the Interpretive Association of Western Colorado, History Colorado and Colorado Div. of Reclamation, Mining & Safety to help determine how best this unique western slope artifact can be preserved for public education and historic interpretation for future generations.

For more information about the Historic Hanging Flume project please contact Chris Miller, Executive Director, Interpretive Association of Western Colorado at 970-874-6695 or visit www.hangingflume.org

(This story was circulated as a press release on April 20, 2017, and published in the San Miguel Basin Forum).

For more on the hanging flume check out the Unaweep-Tabeguache Scenic Byway Association video here or read some collected musings about our flume fever since 2004.