The Journey Toward BIM - A Personal Collaborative Odyssey · 3D SDS II Model of Structural Steel As part of the preparation of shop drawings, the detailers constructed a 3D model

GPLAStructural Engineers and Builders

1/13/2014Copyright © Gregory P. Luth & Associates The Journey Toward BIM

KL&AKL&A

The Journey Toward BIM - A Personal Collaborative

OdysseyGregory P. Luth, Ph.D, S.E

Gregory P. Luth & Associates, IncSanta Clara, California



The journey 1976 – 2007 and beyond

The journey is fraught with perils that would make Odysseus quaver

Starting point 1976Stanford, State of the art computing is an IBM

21MX minicomputer with 32K memory and a 12” removeable disk, and an 800 bpi magnetic tape drive.



The Early Days 1976 - 1985The Early Days 1976 - 1985

In 1976 I was in St. Louis. We were doing our structural analysis on a main frame computer located at the CDC center in Minneapolis. We sent our data over phone lines at 1200 baud. If there was a thunderstorm anywhere between St Louis and Minneapolis, the data stream was corrupted.

Construction management was the up and coming profession for newly minted engineers

The pin bar was the innovation in use for preparing drawings

We were using our trusty HP calculators which had replaced the slide rule for good in 1973.



One Oxford CenterPittsburgh 50 stories

One Bell CenterSt. Louis 46 stories

1000 Wilson Blvd Virginia 30 stories

The Early Days 1976 – 1985The Early Days 1976 – 1985



When the master builder conceived of a design that exceeded the bounds of common practice, he shouldered the responsibility for developing the enabling construction procedures and details




Tabor Center, Denver, Colorado 1981 – 1985 – Enabling Concepts

Scope

Two square blocks32 story office 40 story office21 story hotel6 story below grade parkingState highway bisects the site

Problem:

How to construct two square blocks 6 stories below grade without interrupting traffic





Enabling Concept:

Build the bridge first

Enabling Detail:

Cased piersPT Floor ConnectionTemporary bracing and sequence




Tabor Center, Denver, Colorado 1981 – 1985 – Enabling Details





Enabling Structural Concept: Rigid Column Flexible Beam





Enabling Structural Concept: Rigid Column Flexible Beam





Composite Concrete Wall with Steel Columns

Detail Concept: Prestressed Panel Zone




Tabor Center, Denver, Colorado 1981 – 1985 – Construction Concept

Construction Concept:

Create “rigid” column in steel building by casting concrete wall in between steel columns at the corners of the elevator shafts. Use simple form panel set against face of columns and cast with the floors.





Composite Concrete Wall with Steel Columns

Detail Concept: Prestressed Panel Zone





ChallengeThe Context

As the result of a collaborative value engineering effort involving the owner, the general contractor, the architect, and the structural engineer, the exterior wall of this 32 story office tower in Denver has been changed from Kasota stone, a light buff colored limestone, to exposed architectural concrete. The contactor will use a custom made climbing form to build the intricate walls of the tower ahead of the floors – named the “chimney” method by the team.

The ProblemHow to build the non-typical curved exterior wall behind the curtain wall on a quarter of the perimeter without investing in another $1 million form system. The curved spandrels are part of the exterior tube that provides lateral resistance for the building and this function must be maintained. The spandrel beams are eccentric to the 42” diameter columns along the curve.




Tabor Center, Denver, Colorado 1981 – 1985 – Enabling Structural Concepts

Solution Use precast curved spandrel beams (5’-8” deep)

spanning to the 42” diameter cast-in-place concrete columns




Tabor Center, Denver, Colorado 1981 – 1985 – Enabling Structural Details

Solution Design beam reinforcing to

provide full continuity at the column joint without interfering with the erection of beams on opposite sides of the column and without increasing the size of the cast-in-place joint

Design joint reinforcing that can be installed from the outside face after the beam and column steel are in place using shear friction principles




Tabor Center, Denver, Colorado 1981 – 1985 – Enabling Construction Concepts

Solution Design a steel column form that

would incorporate saddles to accept the precast spandrel beams and hold them in place until the joint concrete is poured locking the system together

Provide for a fold down panel in the form to allow for installation of the joint reinforcing

Use a high early pea gravel mix to facilitate 1 week/floor cycle




Tabor Center, Denver, Colorado 1981 – 1985 – Form for Typical Wall




Tabor Center, Denver, Colorado 1981 – 1985 – Finished

Product




The Middle Years 1985 - 1995The Middle Years 1985 - 1995

In 1985 the latest technology was CAD. Large architectural and engineering firms had Intergraph running on a $300,000 mini-computer.

Smaller firms were experimenting with PC based analysis and CAD software on 8088 processors





1986 – Rivercenter, San AntonioFirst CAD Project on Integraph



The Middle Years 1985 – 1995The Middle Years 1985 – 1995

1986 manifesto – the office of the future

The centerpiece will be a computing system that integrates design, drafting, and detailing functions. Working at a CRT, the project engineer will block out floor framing and define load areas . . . The design of individual members will be automated with the member sizing, etc., automatically added to the floor plans. When the plans are blocked out they will be pulled off the CAD and finished manually. . . .




1987 – Tampa Convention Center First Autocad project on PC



In 1988 Stanford opens the Center for Integrated Facilities Engineering (CIFE)

• AI – Automated intelligent design, Carnegie Mellon, Hi-Rise

• Automated interpretation of blueprints• “Representation and Reasoning for

Integrated Structural Design”

Build the intelligence into a database that can draw itself any way you want to see it




Harris Concert HallRoof segments generated by radial lines from tent

center tilted with respect to each other in randomgeometric arrangement

65 foot clear span across hall 24 inch structure depth limitation at center span 6 inch of concrete on roof for acoustics Buried up to 40 feet deep Aspen Colorado, 8000 ft elevation Mountain weather Transportation through mountainsFast winter construction schedule

August 1992-June1993Interior finishes are the critical pathLocally available structural steelLocally available ready mixed concrete




Final Section and Free Body Diagram




Strategies Listen to the contractor Maximize repetition Utilize locally available material and labor Tailor construction to skills of contractor Maximize prefabrication Get contractor confirmation of schematic Tailor details to minimize erection time Structural engineer detail complex steel Accelerate weather enclosure Minimize exposed concrete operations




Harris Concert Hall, Aspen, ColoradoArchitect Harry TeagueStructural Engineer GPLA General Contractor Shaw Construction

Success!




The Later Years 1995 - 2005The Later Years 1995 - 2005

In 1995 we merged 2D design and 3D modeling for structural steel shop drawings.




Pueblo Library, Pueblo, Colorado

Pueblo Library

This library is in Pueblo, Colorado. It features a 60 ft. cantilevered canopy and two stories of library stacks spanning over a road. The structural engineer designed the structure for the architect and provided the structural steel shop drawings.




Pueblo Library –3D SDS II Model of Structural Steel

As part of the preparation of shop drawings, the detailers constructed a 3D model of the steel frame using a special purpose software package, SDS II, developed by Design Data, Lincoln, Nebraska. In this case, the steel frames into concrete walls. The software, which was developed for steel fabricators, does not recognize concrete, so the detailers put the walls in as solid steel rectangles to represent the geometric constraints.




Pueblo Library – 3D SDS II Model of Structural Steel

Beam-Column-Braces

Truss over road

Truss connectionSDS II does some things quite well.




Limitations of 3D Modeling

Expansion joint

Where’s the pot bearing?

The current tools have their limitations. There is no substitute for the knowledge of the designer and the designer’s ability to visualize in 3D.

Other things it doesn’t do quite so well.

The structural design had to be generated in 2D drawings that were given to the detailers for them to use in generating the 3D model. Sorry, that’s the way it is. Even with an efficient interface, there is far too much labor in constructing the model to use it as a conceptual design tool.




The real purpose of these 3D models is to generate 2D drawings (shop drawings) of each and every piece of steel on the project for use by the fabricator

Sometimes, CNC data is generated directly from the 3D model and used to run the fabricator’s beam line

So, are these 3D models ever used for “design”?




Frame for Iconic Original tent Designed by Saarinen

Replacement Designed by Harry Teague Architects

Benedict Concert Tent, Aspen

The Music Associates of Aspen wanted to replace the venue for its summer concerts, the venerable and iconic tent designed in the 60’s by Aero Saarinen. The architect’s concept was a modern tent supported on four posts, like Saarinen’s original, but with a sophisticated 70 ft. diameter acoustical disk that would support a modern fabric structure

Harry’s signature, and the engineers’ challenge, was the eclectic mix of curved structural shapes over the stage, which turned out to be far more complicated than his concept sketches




Detailers worked with the architect using 3D SDS II model to develop the architectural steel configuration




The results of this successful collaboration in model space were striking.




While all that was going on, we were “perfecting” our 2D CAD process by incorporating the “pin bar” concept from 1976 into our CAD drawings using XREF’s




Down Town Disney Deck, Anaheim, California

Bldg A

House of Blues

Brennan’s

Bridge

Bldg D

69’ Beam69’ Truss

Bldg EBldg H

Expansion jointWine Bar

Grand Californian Hotel

Ficus Planters

The deck had to be built before any of the buildings were designed. The slab was held down 18” and designed for a 300 psf live load

Slope to drain

Bldg G




DTD Deck PlantersThe Crane (Working from the deck)

The Trees

A Planter From Above

The Same Planter From Below




The Results! Down Down Disney Deck, Anaheim, California




Grand Californian Hotel, Anaheim, CaliforniaArchitect: Urban Design Group, Denver

Disney’s Grand Californian Hotel, the first “themed” hotel by Disney at the original Disneyland, is intended to evoke the architectural style of the Arts & Crafts movement of the early 20th century, albeit on a much grander scale.




Tabor Center Redevelopment, Denver, Colorado

The clearances were worked out based on the escalators submitted by the manufacturer. Recognizing the potential for delay if the escalators didn’t fit, a note on the drawing required the contractor to verify the clearances independently. The contractor declined saying this was the responsibility of the designers.

Escalator

Column removed

Main beam

Cantilevered slabEscalator

Pinch point




Tabor Center Redevelopment, Denver, Colorado

As luck would have it, the manufacturer made a last minute substitution of an escalator that had a deeper truss. He said “nothing” was different, meaning none of the usual things that are of interest. No one checked the truss depth. The problem was found when they tried to install the escalators and found a conflict with the main beam. The problem was resolved by moving the escalator back into the floor approximately 9”.

Corollary: It takes everyone collaborating all the time to make a successful project.

Rule: Details make the difference between success and failure and between great concepts and great buildings.




Charlestown, West Virginia, Penn National parking garage, phases I – III, 2004 – 2005, all 2D




Charlestown, West Virginia, Penn National parking garage, phases IV, 2006, 3D Tekla

The present and beyondThe present and beyond



In 2005 we reached a perceptible tipping point in the industry. 3D design AND detailing was no longer simply an aspiration, but a reality for our practice. We were no longer waiting for the technology to mature. Now we were trying to catch up.






USC Lucas School of Cinematic Arts























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The Journey Toward BIM - A Personal Collaborative Odyssey · 3D SDS II Model of Structural Steel As part of the preparation of shop drawings, the detailers constructed a 3D model