Simulate multiple series on a weekly chart

HTML

<script type="text/javascript" src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/serial.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/themes/none.js"></script>
<div id="chartdiv"></div>

CSS

#chartdiv {
	width		: 100%;
	height		: 500px;
	font-size	: 11px;
}

JavaScript

var chart = AmCharts.makeChart("chartdiv", {
    "type": "serial",
    "theme": "none",
    "dataProvider": [{
        "category": "25 avr. 15\n au 1 mai. 16",
        "value1": 2025,
        "value2": 1800
    }, {
        "category": "2 mai. 16\n au 8 mai. 16",
        "value1": 1863,
        "value2": 1951
    }, {
        "category": "9 mai. 15\n au 15 mai. 16",
        "value1": 1610,
        "value2": 950
    }, {
        "category": "16 mai. 15\n au 22 mai. 16",
        "value1": 1732,
        "value2": 1250
    }, {
        "category": "Friday:\nWeek 20\nWeek 21",
        "value1": 1123,
        "value2": 765
    }, {
        "category": "Saturday:\nWeek 20\nWeek 21",
        "value1": 985,
        "value2": 841
    }, {
        "category": "Sunday:\nWeek 20\nWeek 21",
        "value1": 1400,
        "value2": 1300
    }],
    "valueAxes": [{
        "gridColor":"#FFFFFF",
		"gridAlpha": 0.2,
		"dashLength": 0
    }],
    "gridAboveGraphs": true,
    "startDuration": 1,
    "graphs": [{
        "title": "Week #20",
        "balloonText": "[[title]]: <b>[[value]]</b>",
        "valueField": "value1",
            "fillAlphas": 0.8,
    "lineAlpha": 0.2,
        "type": "column",
        }],
    "chartCursor": {
        "categoryBalloonEnabled": false,
        "cursorAlpha": 0,
        "zoomable": false
    },
    "categoryField": "category",
    "categoryAxis": {
        "gridPosition": "start",
        "gridAlpha": 0
    },
    legend: {}
});