Bethesda Triangle Brian Groark Construction Management Faculty Consultant: Dr. Messner

Bethesda Triangle 14 story apartment building Additional 4 stories below grade for parking 580,000 SF Cast in place concrete structure Offices and retail on plaza level High end apartments on floors

Bethesda Triangle Owner: Bethesda Triangle, LLC CM: Encore Development Construction began on February 14, 2002 Phased occupancy Little site space

Bethesda Triangle

Thesis Overview SIPS Schedule Change emergency generator Change formwork Guidelines for mold prevention

CM Depth Short Interval Production Schedule (SIPS)

Reasons for Using SIPS Lack of solid schedule for the project Project will finish extremely late Needs solid, detailed schedule for all aspects of the project Repetitive floors work well for SIPS

SIPS Create a detailed SIPS schedule for the concrete structure Compare it to the original duration for the structure

SIPS Each floor is broken up into 4 sections Crews follow in progression through all the sections and floors Each section has the same duration

Section Layout

SIPS Floors G4 – plaza level are the same Floors 2 – 14 are the same Each section takes 2 weeks to complete

SIPS

Results Original duration was 44 weeks SIPS duration is 31 weeks Time saved is 13 weeks

Electrical Breadth Change Emergency Generator

Original Generator 2 mega-watt generator Power entire building in the event of a black out Sell extra power back to the grid at times when the costs of running the generator are less than electricity costs

New Generator 350 kilo-watt generator Power only emergency systems Emergency lighting and alarms Fire pump Stairwell pressurization Smoke exhaust Elevator

Initial Costs 2 mega-watt – $540, KW - $40,000

Cost Analysis

Costs of running the generator to power the building were compared to purchasing electricity on an hourly basis

Results No profit is shown from running the generator Price of diesel fuel has increased

Recommendation Use proposed generator Initial cost savings of approximately $500,000

Structural Breadth Change Formwork System

Original Formwork Traditional formwork Built in place with shoring Stripped and re-shored

New Formwork System Symons flying truss system Large aluminum forming tables are flown into position with a crane Much higher productivity

Slab Original slab was a flat slab with drop panels Flying truss system can only be used with flat plate slabs Slab was redesigned to a 10” flat plate to accommodate the new forming system

Productivity With a crew of six workers: Hand set system – 544 sq ft per day Flying truss system – 7500 sq ft per day

Comparison Form costs Slab Costs

Results Total cost savings of approximately $950,000

Research Mold Prevention Guidelines

Effects of Mold in Buildings Less serious symptoms of toxic mold poisoning Skin rashes Fatigue Coughing Headaches

Effects of Mold in Buildings More serious symptoms of toxic mold poisoning Impaired breathing Memory loss Hearing, speech, and eyesight degradation Loss of balance

Causes of Mold Moisture Leaks Condensation

Guidelines for Prevention 1. Clear details of all exterior penetrations 2. Design must provide for adequate roof drainage 3. No changes to design of enclosure without architects approval 4. Proper slope of grading

Guidelines for Prevention 5. Drywall must remain dry 6. Complete enclosure of building prior to drywall installation 7. Use drywall designed to reduce mold growth 8. Proper inspection 9. Proper operation of equipment

Conclusions SIPS can reduce schedule duration Larger generator is not profitable at current fuel prices Flying truss formwork greatly increases productivity Early mold prevention can save costly repairs in the future

Questions