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© CADFEM 2016

Yeongsan 3 Floating Sector Gate

Rob Pitt, Associate Director, KGAL Consulting Engineers Ltd

1st CADFEM ANSYS Simulation Conference, United Kingdom

2nd & 3rd November 2016 – Oxford Spires Hotel, Oxford

General Introduction to KGAL

• KGAL began trading in 1990

• Company built through organic growth and acquisition

• Just over 40 part time and full time staff

• 3 Regional offices in the UK

• Significant UK-based workload

• Major ongoing overseas contracts

• Current annual turnover of £3m

General Introduction to KGAL

We specialise in all structural, mechanical, hydraulic and electrical aspects relating to:

• River and Dam Engineering• Hydroelectric Engineering • Flood Defence Gates• Asset Surveys• Marina Gates• Docks, Ports and Harbour Gates• Bridges and Linkspans• Special Purpose Machinery

General Introduction to KGAL

We specialise in all structural, mechanical, hydraulic and electrical aspects relating to:

• River and Dam Engineering

• Hydroelectric Engineering – Water to Wire

• Flood Defence Gates

• Asset Surveys

• Marina Gates

• Docks, Ports and Harbour Gates

• Bridges and Linkspans

• Special Purpose Machinery

• Australia• Brunei• China• India• Iraq• Ireland• Jersey• Korea• Kuwait• Laos• Lesotho

• Malawi• Malaysia• Mexico• New Zealand• Norway • Oman• Singapore• South Korea• Thailand• Turkey• United States of America• Vietnam

We have worked or are working in the following Countries:

Project Brief

• Flood defence project in South Korea• Navigable channel joining Yeongsan and Yeongam rivers• Design and construct a pair of Floating Sector Gates

• KGAL retained by Korean consultant BSR Engineering • Outline design previously prepared by Arcadis• KGAL to prepare the detailed engineering design

Gate Dimensions

To enable articulation of across the river each leaf is buoyant enabling it to float into position and then be scuttled.

Each gate revolves around a spherical bearing to take up the varying river levels and buoyancy conditions that it will be exposed to.

At the time of design there was only one other similar structure built in the world, the Maeslant Barrier in Rotterdam.

• Clear navigable span is 60m

• The radius of each gate is 34m

• They stand just over 8m tall

• Each gate leaf weighs 286 tonnes

Gate Loads

In order to determine the adequacy of the existing outline design a full definition of the primary and secondary loads which may be applied to the gate was prepared.

The key primary loads identified were:

• Hydrostatic water pressure• Self weight• Wave loading• Water ballast• Various seismic elements

Using these primary loads, it was then possible to define all of the various load combinations that the structure would be required to withstand.

Gate Loads

LOAD TYPE YEONGSANSIDE

YEONGAMSIDE

Hydrostatic head +0.96mAD(N) - 1.45mAD(N)

Self weight of Gate 2786 kN -

Wave load (above +0.96mAD level)

0.7 m -

Load Combination Case A

Gate closed with maximum on-seating hydrostatic load

(sector gate arms in compression) with ballast tanks full and

tidal tanks open including Waves

Load Case A is the most onerous on the gate structure, the

hinge bearing and the hinge support structure.

Load Case A will therefore be used as the Design load Case for

the ‘normal’ on-seating condition.

Gate Loads

LOAD TYPE YEONGSANSIDE

YEONGAMSIDE

Hydrostatic head -1.35mAD(N) +0.82mAD(N)

Self weight of Gate 2786 kN -

Wave load (above +0.82mAD level)

- +0.65m

Load Combination Case C

Gate closed with maximum off-seating hydrostatic load

(sector gate arms in tension) with ballast tanks full and

tidal tanks open including Waves

Load Case C is the most onerous on the gate structure,

the hinge bearing and the hinge support structure.

Load Case C will therefore be used as the Design load

Case for the ‘normal’ off-seating condition.

Gate Loads

LOAD TYPE YEONGSANSIDE

YEONGAMSIDE

Hydrostatic head +0.96mAD(N) -1.45mAD(N)

Self weight of Gate 2786 kN -

Seismic Wave + Present Not present

Seismic Water Pressure Variation Present Not present

Load Combination Case N

Seismic with on-seating hydrostatic load, gate closed, ballast present

Load Case N will therefore be used as the Design load

Case for the ‘extreme’ on-seating condition.

Gate Loads

LOAD TYPE YEONGSANSIDE

YEONGAMSIDE

Hydrostatic head -1.35mAD(N) +0.82mAD(N)

Self weight of Gate 2786 kN -

Seismic Wave Present Not present

Seismic Water Pressure Variation Present Not present

Seismic Inertia Force Present Not present

Load Combination Case P

Seismic with off-seating hydrostatic load, gate closed, ballast present

Load Case P will therefore be used as the Design load

Case for the ‘extreme’ off-seating condition.

Load Case Summary

In all a total of 16 Combination Load Cases were defined.

By inspection and assessment, it was determined that Load Cases A, C, N & P being the most onerous would be used in the analysis.

The loads on the gate structure, the hinge bearing loads and the resultant loads imposed onto the civil structure were analysed using ANSYS Workbench Linear Static Analysis.

Other Load Cases were considered when analysing the strength of individual elements of the gate structure such as the skinplate and skinplate stiffeners.

Magnitude of unfactored forces:

• Yeongsan river side 6842kN per gate• Yeongam river side 4450kN per gate

Symmetrical Half Model

Having produced a sensible and coherent 3D model of the

current design in Solidworks this was imported into ANSYS in

.sat format.

Due to the size and complexity of the model a symmetrical half

model was used to reduce the solving time.

Half Model Mesh

.

ANSYS was used to create an automatic solid element mesh.

Artificial constraints were applied to the model to represent real

life contacts and loads were applied to represent real life loading

conditions

Meshing on Arm Members

.

The mesh density was manually set in several areas to enable the stress

distribution within the structure to be accurately assessed.

The mesh itself consists of 3,146,151 nodes and 1,288,975 elements.

Loads and Constraints – Load Case N

Section view through trailing edge of gate structure showing stiffening members and man access tubes.

Deformation – Load Case N

Von Mises Stress – Load Case NOutline Design

Structural Design - Gate Arms

Outline Design KGAL Design

The outline design for the transition plates between the gate arm tubes and the bearing plate did not contain the load transfer path.

KGAL have increased the length of the transition plate

Structural Design - Gate Arms

Outline Design KGAL Design

FEA results showed that the outline design had high stress concentrations on the inside of the gate arm tubes at the joint by the hinge bearing.

KGAL have added internal stiffening tubes at each joint to reduce stress level.

Structural Design - Gate Arms

Outline Design KGAL Design

Results showed that the outline design had high stress concentrations on the underside of the main gate arm tubes at the joint with the gate body.

KGAL have added internal stiffening tubes at each joint to reduce stress level.

High Punching Shear

from brace

Structural Design - Gate Arms

Outline Design KGAL Design

Results showed that the outline design had high stress concentrations on the underside main gate arm tubes at the joint with the diagonal tube braces.

KGAL have added internal stiffening tubes at each joint to reduce stress level.

Structural Design – Gate Body

KGAL Design

Section view through trailing edge of gate structure showing stiffening members and man access tubes.

Structural Design – Gate Hinge Bracket

Gate Hinge Bracket - Constraints

Constraints applied though fixing bolt holes

Self weight applied

Gate Hinge Bracket – Applied Forces

Outline Design KGAL Design

External forces applied to bracket in line with the maximum loads identified from the Load Case assessment.

Gate Hinge Bracket – Deformation

Deformation predicted for Load Case N

Gate Hinge Bracket – Von Mises Stress

Outline Design KGAL Design

Von Mises stresses for Load Case N

Localised stresses identified in excess of allowable values

Re-design required

Gate Hinge Bracket - Realisation

Outline Design KGAL Design

FEA results showed that the outline design had high stress concentrations on the

Gate Arm Stiffening Collars - - Realisation

Outline Design KGAL Design

FEA results showed that the outline design had high stress concentrations on the

Gate Arm to Hinge Transitions - Realisation

Outline Design KGAL Design

FEA results showed that the outline design had high stress concentrations on the

The finished article!

Outline Design KGAL Design

FEA results showed that the outline design had high stress concentrations on the

The finished article!

Thank you, any questions?