Category Archives: Pipe Bending

Hot and Cold Steel Bending for a Fountain Sculpture

Each spring my wife and I take a short vacation in California. While there we usually spend a few days on the campus of Stanford University. While walking the campus grounds this spring, a sculpture/fountain caught my eye. We had walked this way many times in past years, but I had not seen this fountain before. It could be that it is a new fountain, or it could be that I had just not noticed it, since it is a fountain, and most of the fountains had been shut down due to the drought in California the last 3 years. With a rain filled winter season, the drought in California has come to an end, and the campus fountains, silent for the last few years have come to life.

This fountain sculpture is simple, yet powerful. The “Cardinal” color and the simple form is eye catching. Employed by a bender/roller, a company that specializes in curving and/or bending structural metal shapes, the fact that this fountain sculpture was designed with curved material had a special interest. In doing some online research I found that the fountain is officially called the Shumway Fountain, but is known to most as the “Red Hoop Fountain”.

Red Hoop Fountain

The Red Hoop Fountain consists of 2 vertical supports, rising about 10 ft above the base of the fountain pool. Each vertical element then has a 90-degree bend, which transitions into the hoop or large horizontal ring. Based on some on-site detective work, I figured the Red Hoop Fountain was made from 12” pipe (12.75 inch outside diameter). The bends from the vertical to the horizontal were either produced by rotary draw bending, or by induction bending. Rotary draw bending is where the material is bent or wrapped around a specific set of dies/tooling. Induction bending is a process where heat, created by an induction coil, is used to heat the metal in a narrow section, which is then bent slowly to a specific radius and immediately cooled (quenched) with water. I would figure these 90-degree bends were done on an induction bender. The horizontal hoop was most likely curved on a section bender. A section bender is usually a 3-roll bending machine that curves/bends the material using pressure, and is done without heating the material. These 3 elements were then welded together to form this simple yet unique fountain sculpture.

The next time you are near Palo Alto, CA, take a few moments to visit the Red Hoop Fountain at Stanford University!

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Giant Size NFL Helmets

The 2016 NFL season recently kicked off in September. With successful baseball and hockey teams, Chicagoans are hoping that the Bears will take home a few more wins this year. While we keep our fingers crossed for the Bears this season, we are flashing back to last April when Chicago proudly hosted the 2015 NFL Draft at the Auditorium Theatre.

The city was buzzing with fans supporting their football team during the draft. One popular spot was Pioneer Court, an open area along Michigan Avenue that housed 32 giant NFL team helmets during the draft for fans to take pictures with. Continue reading Giant Size NFL Helmets

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Pipe Bending Techniques to Avoid Rippling

Because of its symmetrical nature, pipe can be bent to consistent radii with no distortion, but several things need to be taken into account in order to avoid rippling. In part one of this blog post, we discussed why rippling occurs and what material should be used to avoid it. Once the best material has been determined, a pipe bending company must use the right machine, tooling and methods in order to avoid distortion. Continue reading Pipe Bending Techniques to Avoid Rippling

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How to Avoid Rippling when Pipe Bending

Rippling on the surface of a pipe is a somewhat common problem that occurs during bending operations. Learning about the reasons behind the rippling can help avoid this issue.

Ripples are caused by high levels of compressive force on the inside of a pipe or tube with thin wall thickness. Thicker pipe walls can withstand higher compressive forces on the inside of a bend without distorting or wrinkling. With custom rolled pipe, material on the outside of the bend stretches – this causes wall thinning. The material resists this thinning and as a result the outside surface of the bend wants to cave in. This causes the flawed profile shape we know as ovality or distortion. Continue reading How to Avoid Rippling when Pipe Bending

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Galvanize Pipe Jackets Reinforce Communication Towers

A 167’-7” tall, Verizon Wireless communications tower, atop Smelter Mountain in Durango, Colorado required a structural upgrade on its 3 existing tower legs. The tower had originally been built with 2” to 3” standard structural pipe as its supporting legs, but after years of cyclical wind loads it was determined that the existing tower legs needed a structural upgrade. In order to reinforce the tower’s legs, engineers devised a plan to weld pipe jackets to the outer half of the existing legs, which can be seen in the diagram below.

Pipe jackets are a common term for pipe split or halved into 180 degrees. They are commonly used for heat exchangers and or coils welded to the outside of tanks. For this project the split/halved pipes are referred to as 180deg cut pipe. Various size pipes were to be split into halves, from 3” to 5” XXH and then straightened in order to surround the outer half of the existing tower legs. The additional support from the reinforcing 180deg cut pipe increases the stiffness of the tower 12x from its original design.

The pipe was split into 180deg cut pipe by way of a gantry track plasma cutting system. The pipe is fixed in order to restrict its movement when cutting and once the torch strikes an arc the movement of the cutting head is automated to eliminate any deviation from the cut line. Due to residual stresses within the pipe, from its melting and manufacturing at the mill, the pipe springs and twists open once it is fully split.  This is commonly known in the industry as the banana peel effect, and must be corrected by way of straightening. Most structural steel fabricators have the equipment to split the pipe through some sort of track cutting system, either flame or plasma, but it is the straightening of the halved pipes back to within, or better than, mill tolerance that is the challenging aspect of splitting pipe into 180deg cut pipe. For this, most fabricators seek out a bender/roller as they have the necessary equipment to bend, curve and straighten structural steel.  With the proper tooling, a machine which is normally used for bending steel can also be used for the opposite, to straighten out existing curvature.

In this case, a 3-Roll section bender with a special tooling setup was used to straighten the pipe and it was straightened to 1/8” over 10ft of length. After the 180deg cut pipes were straightened, they were bundled and sent to a galvanizer. The halved pipes were then hot dip galvanized for corrosion protection after installation. The galvanized reinforcing pipe jackets were then shipped to a terminal in Durango, Colorado where they were staged for pickup once the steeplejacks were ready for installation.

Straightened and Galvanized Steel Pipe
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Excellence in Structural Engineering Award Goes to Institute of Environmental Sustainability

Structural Engineers Association of Illinois (SEAOI) gives out an award every year to a project it feels helps encourage engineering education and advances the art and science of structural engineering. Loyola’s recently constructed Institute of Environmental Sustainability (IES) won the “Best Project” award given out by SEAOI for the Excellence in Structural Engineering Awards Competition. The judge commented that “the winter garden is an elegant curved glass enclosure with a minimized amount of structure to allow unobstructed views. The environmentally responsible IEC integrates academic and residential components of university to create space for an exciting and delightful whole student experience”.

IES – Loyola University Chicago

The crown jewel of IES is the winter garden. The winter garden is a 3,100 square foot urban agricultural greenhouse. The structure is designed using nine elliptically curved trusses that are made out of 8” SCH 80 pipe connected to 5” SCH 40 pipe though a triangular cross section configuration of a double top chord and single bottom chord system. The design of the continuously curving trusses helps minimize the amount of structure needed to hold up the glass curtain wall skin. The top roof portion of the greenhouse incorporates pipes curved to a very large 250ft radius to help maximize sunlight in the winter garden’s growing area while at the same time try to produce minimal glare to surrounding buildings. Also there is a tight 12 ft radius 90 degree bend at one end that goes down into an S shaped curve. This curvature in the steel pipe trusses design helps with passive ventilation. When you walk into the building you will notice the temperature. You are in an unconditioned environment that is not heated or cooled. The winter garden is shaped to assist natural ventilation with open end windows at both ends of the trusses. This unique curved shape of the winter garden also facilitates rain water harvesting. Water falling on the curved roof easily flows into a 3,000 gallon cistern located on the first floor. The water is then reused in the greenhouse operations for irrigation, landscaping and for flushing the toilets located off the lounge.

Curved 8″ SCH 80 and 5″ SCH 40 Pipe

In the greenhouse there will be two aquaponic systems. There are also two vertical farming installations where food crops are grown for harvest on a wall mounted lattice structure. The ecological system will grow fish and produce for food. Students taking courses in related fields will work to identify what to grow in these systems and how to process them for market. Students maintaining these gardens will sell the produce at Loyola’s famers market and through the Engrained Café. The IES is an innovative and interactive learning environment that demonstrates how students can participate actively within, as well as help to create a living/learning green community.

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Circuit of Americas Observation Tower Wins IDEAS2 Award

Innovative Design in Engineering and Architecture with Structural Steel (IDEAS2) awards are sponsored by the American Institute of Steel Construction in recognizing projects where structural steel has been utilized in an innovative manner. This year the winners were chosen from nearly 100 submissions from architectural, engineering and construction firms throughout the U.S. This year Circuit of the Americas (COTA) Observation Tower won in the category for projects less than $15 million. The COTA is a 3.4 mile motor racing circuit, the first purpose-built F1 track in the U.S. that is located just outside of Austin TX. The land mark 251 foot tall observation tower was designed by Miro Rivera Architects to give spectators unrestricted views across the racetrack’s twisting bends. The platform (which has a glass floor) provides a 360 degree panorama view of the circuit and has a capacity for 10,000 spectators.

COTA View from Above

The circuit of the Americas observation tower won the award because it combines creativity, economic and technical achievement through the use of structural steel. The observation tower is very creative in how it uses a veil like structure made out of 18 bright red closely spaced HSS 8.625” OD structural pipe that are curved running down the full height of the tower. The pipes act as a canopy for both the platform and the stage below. The design of the curved pipes was inspired by the visual imagery of sports cars and movement. The red pipes running along the tower mimic the streaks of lights trailing racecars at night time. While ostensibly an architectural feature, the veil also serves as an outrigger column for lateral load resistance via a series of struts and rods that connect it to the main tower. The tower contains approximately 385 tons of steel. The observation tower also had a technical achievement through the use of fully connected Tekla Structures program.

COTA Structural Steel Canopy

Due to the tight 10 month time frame from owner approval to race day, the complex tower structure design had to be conveyed to the fabricator so they could erect the canopy without confusion. Generally in the steel fabrication construction industry paper drawings are delivered to the steel fabricator to interpret and build, but this case they were able to bypass this step and print shop drawings directly from the model. To increase efficiency and reduce cost of bending each 8 inch steel pipe to the architects initial drawings the program helped work with a bender roller to break large radii into segments. There were a total of 70 curved 8” sch 40 pipes that start out at a tight 96” centerline radius and then get a slightly looser 360” radius before opening up to a large 1,349” radius at the bottom of the tower. The fabricator worked directly with a detailing service to electronically transfer the model into detailed fabrication shop drawings that showed the pipes in different curved sections. The construction manager, Austin Commercial, estimated that the integrated delivery process saved three months over a more conventional process. COTA is more than just a racetrack; it has become a major economic driver in Central Texas. On their website they state that from October 2013 to September 2014, COTA brought in $900 million to the Austin metropolitan area ($731 million for events and $166 million attributed to operations). During that time COTA hosted six motorsports, 18 concerts, 110 track rentals and other events that helped create 9,100 jobs through annual activities and operations.

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Curved Stainless Steel and Chicago’s Draft Town

The city of Chicago has prepared for the media spotlight this weekend as the NFL has moved its annual draft events from New York to the heart of the Midwest this year.  Tourists and locals alike can visit Grant Park to take part in a number of activities as part of the “Draft Town” built up specifically for this event.  While the draft itself is taking place at nearby Roosevelt University, the free fun takes place in the park.  Events include a flag football festival, Super Bowl museum, football celebrity autographs, and even a lightshow at the famous Buckingham Fountain, as the city changes the colors on the fountain to represent the NFL team which is currently on the clock waiting to draft.

NFL Draft Town

While visiting Grant Park, many patrons will have the chance to view some of Chicago’s finest examples of curved steel.  Always a tourist attraction, the nearby Millennium Park is an extension of Chicago’s Grant Park and contains the famous Cloud Gate sculpture and Pritzker Pavilion.  Cloud Gate, or “The Bean” as it is affectionately known, displays a 3/8″ thick curved stainless steel façade that has been polished to a mirror finish.  The complex topological curved steel surface required computer and robotic assistance to create properly.  The plates were fabricated so precisely that no on-site cutting or filing was necessary when lifting and fitting them into position to be welded together.

Cloud Gate

Nearby Pritzker Pavilion features both a curved stainless steel band shell with a ribbon like effect, as well as curved arches made from rolled pipe which varies in diameter from 12 to 20 inches.  The curved pipe trellis allows for an open lawn structure to support the speaker system and has become very popular for local music and film events.  The use of curved steel pipe was preferred by designer Frank Gehry over the alternative of using vertical columns or pipes to support the speakers as it worked together with the curved band shell more aesthetically.

Pritzker Pavilion
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