google.load('visualization', '1', {
  packages: ['corechart', 'bar'],
  callback: drawBarChart
});

function drawBarChart() {
    var data = google.visualization.arrayToDataTable([
        ['Structure', 'Estimated', 'Actual'],
        ['hours', 6, 8],
        ['hours2', 20, 18],
    ]);

    var options = {
        chart: {
            title: 'Structures by Hours',
            subtitle: 'Estimated vs Actual',
        },
        vAxis: {
            title: 'Hours',
            ticks: [-10, 0, 4, 0, 8, 10, 12, 14, 16, 18, 20]
        }
    };

    var chart = new google.visualization.ColumnChart(document.getElementById('columnchart_hours'));
    chart.draw(data, options);

    var chart2 = new google.charts.Bar(document.getElementById('columnchart_hours2'));
    chart2.draw(data, google.charts.Bar.convertOptions(options));
}