Big Beam Competition


The Fabrication

Tray2024.jpg (129306 bytes) Laying the formwork for the beam.

Tray2025.jpg (111729 bytes) Getting forms ready.

Tray2027.jpg (122740 bytes) Layout of reinforcing steel.

Tray2029.jpg (125618 bytes) Forming up.

Tray2033.jpg (124340 bytes) Work on reinforcing steel.

Tray2034.jpg (87689 bytes) Rebar with foam insert.

Tray2035.jpg (93898 bytes) Form for I-section.  Foam maintained full box section at center of beam to resist moment.

Tray2036.jpg (58251 bytes) Another look at the formwork.

Tray2037.jpg (136951 bytes) Insertion of rebar into form.

Tray2038.jpg (100287 bytes) Rebar in forms.

Tray2039.jpg (121249 bytes) Reinforcing steel in forms, preparing for mix.

Tray2041.jpg (131988 bytes) Two formed beams:  one box beam, one I-shape.

Tray2043.jpg (131751 bytes) Another shot of formwork.

Tray2044.jpg (87883 bytes) Preparing to pour.

Tray2045.jpg (106434 bytes) Mixing hopper.

Tray2046.jpg (93596 bytes) Concrete mix in hopper.

Tray2047.jpg (103999 bytes) The mix.

Tray2048.jpg (128117 bytes) Pouring concrete into forms.

Tray2050.jpg (133904 bytes) Mike overseeing proper techniques.

Tray2051.jpg (125957 bytes) Freshly poured beams.


The Testing

P1010001.jpg (124192 bytes) The setup of the reaction frame.  Two beams to be tested:  one I-beam and a box beam, both prestressed concrete.

P1010002.JPG (138571 bytes) Another view of the setup before testing.

P1010003.jpg (143902 bytes) Getting Enerpac hydraulic cylinder into place.  The I-beam was tested first.

P1010004.jpg (133587 bytes) Each beam rested on elastomeric bearing pads.  They were 15 feet in length with a clearspan of 14'6".

P1010005.jpg (152107 bytes) Mike and Lisa setting up the instruments to measure vertical displacement.

P1010007.jpg (100829 bytes) Enerpac in place, ready to commence testing.  The jack has a maximum capacity of 100 kips.

P1010008.jpg (91998 bytes) A view of the setup just before testing.

P1010009.jpg (130989 bytes) Another shot of the test setup.

P1010010.jpg (145354 bytes) Mike, Bryan, and Nate, all members of the Big Beam Team.

P1010011.jpg (102747 bytes) Dr. Howard checking alignment of jack.

P1010012.jpg (96062 bytes) In the testing phase.

P1010013.jpg (111932 bytes) Load being applied........

P1010014.jpg (90893 bytes) Close-up of the the test beam during testing.

P1010015.jpg (100614 bytes) Displacement occurring, cracks evident and marked.

P1010016.jpg (108991 bytes) Mike working his magic with the camcorder.

P1010017.jpg (106674 bytes) Adjustment of the gauges.  Cracks propagating, deformation obvious.

P1010018.jpg (91859 bytes) Proliferation of cracks, more deformation.

P1010019.jpg (106331 bytes) Still testing.

P1010020.jpg (139268 bytes) Overall view.  Deformation easily seen.

P1010021.jpg (124764 bytes) More load......

P1010022.jpg (134503 bytes) More load........

P1010023.jpg (100165 bytes) A lot of displacement evident.  Compression in top of beam causes chunks of concrete to fly off, can be seen around beam.

P1010024.jpg (107827 bytes) Failure of I-beam.

P1010025.jpg (117359 bytes) Removal of testing equipment from I-beam.

P1010026.jpg (79567 bytes) Failed concrete at center of I-beam.

P1010027.jpg (95980 bytes) Close-up of failure, bent compressive reinforcing steel showing.

P1010028.jpg (110328 bytes) Another close-up with chunk of expelled concrete:  sheared through aggregate.  Good mix design.

P1010029.jpg (99172 bytes) Next, the box beam.  Load applied, cracks marked.

P1010030.jpg (109565 bytes) Propagation of cracks.

P1010031.jpg (151915 bytes) Deflection of box beam during testing.  Yes, that's Dave Leake in the background.

P1010032.jpg (113297 bytes) More deformation, failure of concrete in tension.

P1010033.jpg (116981 bytes) Complete failure of beam, removal of testing equipment.  Reinforcing steel exposed.

P1010034.jpg (107975 bytes) Removal of jack from loading frame.

P1010035.jpg (108138 bytes) Two beams, side-by-side.  Box beam mix also sheared aggregate:  good mix.

P1010036.jpg (108346 bytes) Close-up of box beam failure, bent rebar.

P1010037.jpg (136892 bytes) Close-up of both beams, aggregate sheared.

P1010038.jpg (118329 bytes) Overall view of testing facility.